KVM: arm64: Generalise kvm_pgtable_stage2_set_owner()

KVM: arm64: Generalise kvm_pgtable_stage2_set_owner()

kvm_pgtable_stage2_set_owner() can be generalised into a way to store
up to 59 bits in the page tables alongside a 4-bit 'type' identifier
specific to the format of the 59-bit payload.

Introduce kvm_pgtable_stage2_annotate() and move the existing invalid
ptes (for locked ptes and donated pages) over to the new scheme.

Tested-by: Fuad Tabba <tabba@google.com>
Tested-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260330144841.26181-22-will@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>