dev, x86: Delete the now unused X86 specific interrupt pins/lines.

Change-Id: I3915f0ad673119b551dcc4c5cedec180a9b88735
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20702
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

dev, x86: Convert x86 devices to the generic int pins.

Change-Id: I4551ad00cf205c31555c90b53e87bc206a8d8729
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20701
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

style: remove trailing whitespace

Result of running 'hg m5style --skip-all --fix-white -a'.

x86: Add missing explicit overrides for X86 devices

Make clang >= 3.5 happy when compiling build/X86/gem5.opt on OSX.

misc: Remove redundant compiler-specific defines

This patch moves away from using M5_ATTR_OVERRIDE and the m5::hashmap
(and similar) abstractions, as these are no longer needed with gcc 4.7
and clang 3.1 as minimum compiler versions.

sim: Refactor the serialization base class

Objects that are can be serialized are supposed to inherit from the
Serializable class. This class is meant to provide a unified API for
such objects. However, so far it has mainly been used by SimObjects
due to some fundamental design limitations. This changeset redesigns
to the serialization interface to make it more generic and hide the
underlying checkpoint storage. Specifically:

* Add a set of APIs to serialize into a subsection of the current
object. Previously, objects that needed this functionality would
use ad-hoc solutions using nameOut() and section name
generation. In the new world, an object that implements the
interface has the methods serializeSection() and
unserializeSection() that serialize into a named /subsection/ of
the current object. Calling serialize() serializes an object into
the current section.

* Move the name() method from Serializable to SimObject as it is no
longer needed for serialization. The fully qualified section name
is generated by the main serialization code on the fly as objects
serialize sub-objects.

* Add a scoped ScopedCheckpointSection helper class. Some objects
need to serialize data structures, that are not deriving from
Serializable, into subsections. Previously, this was done using
nameOut() and manual section name generation. To simplify this,
this changeset introduces a ScopedCheckpointSection() helper
class. When this class is instantiated, it adds a new /subsection/
and subsequent serialization calls during the lifetime of this
helper class happen inside this section (or a subsection in case
of nested sections).

* The serialize() call is now const which prevents accidental state
manipulation during serialization. Objects that rely on modifying
state can use the serializeOld() call instead. The default
implementation simply calls serialize(). Note: The old-style calls
need to be explicitly called using the
serializeOld()/serializeSectionOld() style APIs. These are used by
default when serializing SimObjects.

* Both the input and output checkpoints now use their own named
types. This hides underlying checkpoint implementation from
objects that need checkpointing and makes it easier to change the
underlying checkpoint storage code.

dev: prevent intel 8254 timer counter events firing before startup

This change includes edits to Intel8254Timer to prevent counter events firing
before startup to comply with SimObject initialization call sequence.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

dev: make BasicPioDevice take size in constructor

Instead of relying on derived classes explicitly assigning
to the BasicPioDevice pioSize field, require them to pass
a size value in to the constructor.

Committed by: Nilay Vaish <nilay@cs.wisc.edu>

x86: Add checkpointing capability to devices

Add checkpointing capability to the Intel 8254 timer, CMOS, I8042,
PS2 Keyboard and Mouse, I82094AA, I8237, I8254, I8259, and speaker
devices

Make commenting on close namespace brackets consistent.

Ran all the source files through 'perl -pi' with this script:

s|\s*(};?\s*)?/\*\s*(end\s*)?namespace\s*(\S+)\s*\*/(\s*})?|} // namespace $3|;
s|\s*};?\s*//\s*(end\s*)?namespace\s*(\S+)\s*|} // namespace $2\n|;
s|\s*};?\s*//\s*(\S+)\s*namespace\s*|} // namespace $1\n|;

Also did a little manual editing on some of the arch/*/isa_traits.hh files
and src/SConscript.

X86: Rework interrupt pins to allow one to many connections.

X86: Set up a mechanism for the I8254 timer to cause interrupts.

X86: Change I8254 and PCSpeaker devices from subdevices to SimObjects and eliminate subdevices.