xen/grant-table: Move xlated_setup_gnttab_pages to common place

xen/grant-table: Move xlated_setup_gnttab_pages to common place

Move xlated_setup_gnttab_pages to common place, so it can be reused by
ARM to setup grant table.

Rename it to xen_xlate_map_ballooned_pages.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Julien Grall <julien.grall@arm.com>
Tested-by: Julien Grall <julien.grall@arm.com>
(cherry picked from commit 243848fc018cb98c2a70c39fe1f93eb266c79835)
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Orabug: 24820937