ANDROID: BACKPORT: KVM: arm64: Turn kvm_pgtable_stage2_set_owner into kvm_pgtable_stage2_annotate

kvm_pgtable_stage2_set_owner() could be generalised into a way
to store up to 63 bits in the page tables, as long as we don't
set bit 0.

Let's just do that.

Signed-off-by: Marc Zyngier <maz@kernel.org>
[willdeacon@: Fix S2MPU conflict in host_stage2_set_owner_locked()]
Bug: 209580772
Change-Id: I4e42d149b457870c35a5ae0f77e14c95dee16b4d
Signed-off-by: Will Deacon <willdeacon@google.com>