ANDROID: KVM: arm64: Don't update IOMMUs unnecessarily

When handling host stage-2 faults the hypervisor currently updates the
CPU _and_ IOMMUs page-tables. However, since we currently proactively
map accessible PA ranges into IOMMUs, updating them during stage-2
faults is unnecessary -- it only needs to be done during ownership
transitions. Optimize this by skipping the IOMMU updates from the host
memory abort path, which also reduces contention on the host stage-2
lock during boot and saves up to 1.1 sec of boot time on Pixel 6.

Bug: 232879742
Change-Id: I71f439311fe9573005efcc9529a2be53f21993a4
Signed-off-by: Quentin Perret <qperret@google.com>