KVM: arm64: Open-code kvm_mmu_write_protect_pt_masked()

Move the functionality of kvm_mmu_write_protect_pt_masked() into its
caller, kvm_arch_mmu_enable_log_dirty_pt_masked().  This will be used
in a subsequent commit in order to share some of the code in
kvm_arch_mmu_enable_log_dirty_pt_masked().

Signed-off-by: Ricardo Koller <ricarkol@google.com>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Link: https://lore.kernel.org/r/20230426172330.1439644-11-ricarkol@google.com


Signed-off-by: Oliver Upton <oliver.upton@linux.dev>