arch-arm: Fix GICv3 List register mapping Change-Id: I870104cf27cc9ba28763adc5b43ff850c1ea279f Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/65172 Reviewed-by: Jason Lowe-Power <power.jg@gmail.com> Maintainer: Jason Lowe-Power <power.jg@gmail.com> Tested-by: kokoro <noreply+kokoro@google.com>