ANDROID: KVM: arm64: Don't filter out KVM_FUNC_MMIO_GUARD_MAP hypercalls

If a KVM_FUNC_MMIO_GUARD_MAP hypercall from a protected guest fails at
EL2 due to running out of page-table memory, the call is forwarded to
the host so that additional memory can be donated using the vCPU's
memcache.

Unfortunately, the host filters out these calls the hypervisor will
replay the guest's HVC instruction forever, making no progress because
it will fail each time.

Avoid filtering out KVM_FUNC_MMIO_GUARD_MAP, in the same way as we
handle the SHARE and UNSHARE hypercalls.

Bug: 262700476
Cc: Keir Fraser <keirf@google.com>
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: Idd14c6bc08a4232939676e3566b79cbc7c927a3a