Adds the O3_ARM_v7a CPU model as an extra option for the `--cpu-type` to `configs/example/arm/baremetal.py`. Change-Id: I717b168945bec22fb5ae17e37c2854df844bcb4f Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/69686 Tested-by: kokoro <noreply+kokoro@google.com> Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>