xen/gntdev: update to new mmu_notifier semantic

Calls to mmu_notifier_invalidate_page() were replaced by calls to
mmu_notifier_invalidate_range() and are now bracketed by calls to
mmu_notifier_invalidate_range_start()/end()

Remove now useless invalidate_page callback.
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Roger Pau Monné <roger.pau@citrix.com>
Cc: xen-devel@lists.xenproject.org (moderated for non-subscribers)
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/xen/gntdev.c

@@ -484,13 +484,6 @@ static void mn_invl_range_start(struct mmu_notifier *mn,
 	mutex_unlock(&priv->lock);
 }
 
-static void mn_invl_page(struct mmu_notifier *mn,
-			 struct mm_struct *mm,
-			 unsigned long address)
-{
-	mn_invl_range_start(mn, mm, address, address + PAGE_SIZE);
-}
-
 static void mn_release(struct mmu_notifier *mn,
 		       struct mm_struct *mm)
 {
@@ -522,7 +515,6 @@ static void mn_release(struct mmu_notifier *mn,
 
 static const struct mmu_notifier_ops gntdev_mmu_ops = {
 	.release                = mn_release,
-	.invalidate_page        = mn_invl_page,
 	.invalidate_range_start = mn_invl_range_start,
 };