xen: mapcache: Break out xen_map_cache_init_single()

Break out xen_map_cache_init_single() in preparation for
adding multiple map caches.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Message-ID: <20240430164939.925307-11-edgar.iglesias@gmail.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
1 file changed