ANDROID: KVM: arm64: Save and restore host sve state in pKVM

Non-protected mode relies on the host to restore its SVE state if
necessary. However, protected VMs shouldn't reveal any
information to the host, including whether they have potentially
dirtied the host's sve state. Therefore, save and restore the
host's sve state at hyp in protected mode.

Currently this behavior applies to protected and non-protected
VMs in protected mode. It could be optimised for non-protected
VMs by applying the same behavior as non-protected mode, which is
to inform the host that it should restore its sve state. But for
now it's kept this way to maintain the same behavior for all VMs
in protected mode.

Signed-off-by: Fuad Tabba <tabba@google.com>
Bug: 278749606
Change-Id: Ifbcc64b387c3f821a6c1047e8c843f6250a3f690