[ Upstream commit 72791ac854fea36034fa7976b748fde585008e78 ]

Add a missing header otherwise compiler warns about missed prototype:

drivers/xen/xlate_mmu.c:183:5: warning: no previous prototype for 'xen_xlate_unmap_gfn_range?' [-Wmissing-prototypes]
  int xen_xlate_unmap_gfn_range(struct vm_area_struct *vma,
      ^~~~~~~~~~~~~~~~~~~~~~~~~
Signed-off-by: NSrikanth Boddepalli <boddepalli.srikanth@gmail.com>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: NJoey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: NJuergen Gross <jgross@suse.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>