ANDROID: KVM: arm64: Wait on S2MPU.STATUS after invalidation

The S2MPU must wait for a v9 device to finish invalidation before
accessing its SFRs. Failure to do so can result in memory transaction
timeouts.

Add a loop that polls the STATUS register while the return value has
the BUSY and ON_INVALIDATING bits set.

Test: builds, boots
Bug: 190463801
Bug: 206761586
Signed-off-by: David Brazdil <dbrazdil@google.com>
Change-Id: I00891dc3a8ad185d29757b8622a053a96237b803