dev-arm: Take LPIs into account when interacting with CPUIF regs

dev-arm: Take LPIs into account when interacting with CPUIF regs

Previous code was not handling LPIs when it came to
activation/deactivation of interrupts.

Change-Id: Ie38f83c66afdc42132679d7e2e5823990f1710d0
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18595
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>