arch-arm: This commit adds Pointer Authentication feature.

arch-arm: This commit adds Pointer Authentication feature.

+ ArmISA.py: Enabling the feature adding  QARMA algorithm as default.
+ faults.cc/faults.hh: Add PACTrapFault
+ includes/insts.isa: Adding new isa files.
+ aarch64.isa: Add decode part for PAC instructions
+ pauth.isa: Isa for PAC instructions
+ misc64.isa: PAC instructions templates
+ miscregs.cc/hh/types: New Registers for PAC Key low/high.
+ types.hh: Modification of system registers that were incomplete
            for ARMv8
+ utility.hh: Add isSecureEL2 enabled. The function is there but will
              always return false for now.
+ pauth_helpers.hh/cc: Implementation of auxiliar functions and derivates.
+ qarma.hh/cc: This functions follow ARMv8 reference pseudo code
              implementing QARMA block cipher algorithms.

Change-Id: I3095a1279204206d9a816a4fb7fc176c18f9680b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/25024
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>