mm/uffd: fix comment in handling pte markers

The comment is obsolete after f369b07 ("mm/uffd: reset write
protection when unregister with wp-mode", 2022-08-20).  Remove it.

Link: https://lkml.kernel.org/r/20230215205800.223549-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: xzpeter

mm/memory.c

@@ -3627,9 +3627,7 @@ static vm_fault_t pte_marker_handle_uffd_wp(struct vm_fault *vmf)
 {
 	/*
 	 * Just in case there're leftover special ptes even after the region
-	 * got unregistered - we can simply clear them.  We can also do that
-	 * proactively when e.g. when we do UFFDIO_UNREGISTER upon some uffd-wp
-	 * ranges, but it should be more efficient to be done lazily here.
+	 * got unregistered - we can simply clear them.
 	 */
 	if (unlikely(!userfaultfd_wp(vmf->vma) || vma_is_anonymous(vmf->vma)))
 		return pte_marker_clear(vmf);