ANDROID: KVM: arm64: Fix which features are marked as allowed for protected VMs

Cache maintenance operations are not trapped for protected VMs,
and shouldn't be. Mark them as allowed.

Moreover, features advertised by ID_AA64PFR2 and ID_AA64MMFR3 are
(already) not allowed, mark them as such.

Bug: 278749606
Change-Id: I5b77498002ce5193e5c2893f3e151991e3a523eb
Signed-off-by: Fuad Tabba <tabba@google.com>