system: Pass RAM MemoryRegion and is_write in xen_map_cache()

system: Pass RAM MemoryRegion and is_write in xen_map_cache()

Propagate MR and is_write to xen_map_cache().
This is in preparation for adding support for grant mappings.

No functional change.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Acked-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Message-ID: <20240430164939.925307-14-edgar.iglesias@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>