python: Don't assume SimObjects live in the global namespace

The importer in Python 3 doesn't like the way we import SimObjects
from the global namespace. Convert the existing SimObject declarations
to import from m5.objects. As a side-effect, this makes these files
consistent with configuration files.

Change-Id: I11153502b430822130722839e1fa767b82a027aa
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15981
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>

dev: Fix the SPARC and X86 platform devices.

A recent serial device refactoring changed the name of the parameter
that the terminal device gets attached to on the UART. The x86 and
SPARC platform devices didn't get updated though, and were still using
the old name. This change updates those objects.

Reported-by: Kanad Basu <kanad.kut@gmail.com>
Change-Id: I0824a9df8639062d8561420ea9ffea26b8b7e2e9
Reviewed-on: https://gem5-review.googlesource.com/5781
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

sim: Include object header files in SWIG interfaces

When casting objects in the generated SWIG interfaces, SWIG uses
classical C-style casts ( (Foo *)bar; ). In some cases, this can
degenerate into the equivalent of a reinterpret_cast (mainly if only a
forward declaration of the type is available). This usually works for
most compilers, but it is known to break if multiple inheritance is
used anywhere in the object hierarchy.

This patch introduces the cxx_header attribute to Python SimObject
definitions, which should be used to specify a header to include in
the SWIG interface. The header should include the declaration of the
wrapped object. We currently don't enforce header the use of the
header attribute, but a warning will be generated for objects that do
not use it.

Device: Remove overloaded pio_latency parameter

This patch removes the overloading of the parameter, which seems both
redundant, and possibly incorrect.

The PciConfigAll now also uses a Param.Latency rather than a
Param.Tick. For backwards compatibility it still sets the pio_latency
to 1 tick. All the comments have also been updated to not state that
it is in simticks when it is not necessarily the case.

MEM: Fix residual bus ports and make them master/slave

This patch cleans up a number of remaining uses of bus.port which
is now split into bus.master and bus.slave. The only non-trivial change
is the memtest where the level building now has to be aware of the role
of the ports used in the previous level.

SE/FS: Put platform pointers in fewer objects.

Not all objects need a platform pointer, and having one creates a dependence
on their being a platform object. This change removes the platform pointer to
from the base device object and moves it into subclasses that actually need
it.

Rename SimConsole to Terminal since it makes more sense

Move SimObject python files alongside the C++ and fix
the SConscript files so that only the objects that are
actually available in a given build are compiled in.
Remove a bunch of files that aren't used anymore.