KVM: arm64: Move VMA-related information to kvm_s2_fault_vma_info

KVM: arm64: Move VMA-related information to kvm_s2_fault_vma_info

Mecanically extract a bunch of VMA-related fields from kvm_s2_fault
and move them to a new kvm_s2_fault_vma_info structure.

This is not much, but it already allows us to define which functions
can update this structure, and which ones are pure consumers of the
data. Those in the latter camp are updated to take a const pointer
to that structure.

Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>