KVM: arm64: Probe FF-A version and host/hyp partition ID during init

Probe FF-A during pKVM initialisation so that we can detect any
inconsistencies in the version or partition ID early on.

Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230523101828.7328-3-will@kernel.org


Signed-off-by: Oliver Upton <oliver.upton@linux.dev>