cpu: Added the Multiperspective Perceptron Predictor with TAGE (8KB and 64KB)

Described by the following article:
Jiménez, D. "Multiperspective perceptron predictor with TAGE."
Championship Branch Prediction (CBP-5) (2016).

Change-Id: Ica3c121a4c94657d9015573085040e8a1984b069
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19188
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Ilias Vougioukas <ilias.vougioukas@arm.com>

cpu: Added 8KB and 64KB TAGE-SC-L branch predictor

The original paper of the branch predictor can be found here:
http://www.jilp.org/cbp2016/paper/AndreSeznecLimited.pdf

Change-Id: I684863752407685adaacedebb699205c3559c528
Reviewed-on: https://gem5-review.googlesource.com/c/14855
Reviewed-by: Sudhanshu Jha <sudhanshu.jha@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

cpu: Made the Loop Predictor a SimObject

The Loop Predictor implementation is now a SimObject so that other branch
predictors can easily use it (including LTAGE, which is now using it).
It has also been updated with the latest
available loop predictor implementation from Andre Seznec:

http://www.irisa.fr/alf/downloads/seznec/TAGE-GSC-IMLI.tar

Change-Id: I60ad079a2c49b00a1f84d5cfd3611631883a4b57
Reviewed-on: https://gem5-review.googlesource.com/c/15775
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>