dev-arm: SMMUv3, default CMDQ entries to 128

dev-arm: SMMUv3, default CMDQ entries to 128

From Linux 587e6c10a7ce89a5924fdbeff2ec524fbd6a124b, SMMUv3
implementations in 64-bit platforms must report a minimum of 128 CMDQ
entries via SMMU_IDR1. Otherwise, the SMMUv3 Linux driver returns -ENXIO.

Change-Id: I304aac1b734515b3077003e8d67cc19730afc67f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35297
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>