dev-arm: Relax size constraint on AMBA ID registers

dev-arm: Relax size constraint on AMBA ID registers

This patch is allowing non word sized accesses to the AMBA ID
registers.

Change-Id: I61a7163a3b4120e8dbcdbd6d9b83d33a7996f979
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/31175
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>