cpu: Add first-/non-faulting load support to Minor and O3

cpu: Add first-/non-faulting load support to Minor and O3

Some architectures allow masking faults of memory load instructions in
some specific circumstances (e.g. first-faulting and non-faulting
loads in Arm SVE). This patch adds support for such loads in the Minor
and O3 CPU models.

Change-Id: I264a81a078f049127779aa834e89f0e693ba0bea
Signed-off-by: Gabor Dozsa <gabor.dozsa@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19178
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>