mm/rmap: rename anon_vma_unlock() => anon_vma_unlock_write()

The comment in commit 4fc3f1d66b1e ("mm/rmap, migration: Make
rmap_walk_anon() and try_to_unmap_anon() more scalable") says:

| Rename anon_vma_[un]lock() => anon_vma_[un]lock_write(),
| to make it clearer that it's an exclusive write-lock in
| that case - suggested by Rik van Riel.

But that commit renames only anon_vma_lock()

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mremap.c b/mm/mremap.c
index ebe27a8..463a257 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -135,7 +135,7 @@
 	pte_unmap(new_pte - 1);
 	pte_unmap_unlock(old_pte - 1, old_ptl);
 	if (anon_vma)
-		anon_vma_unlock(anon_vma);
+		anon_vma_unlock_write(anon_vma);
 	if (mapping)
 		mutex_unlock(&mapping->i_mmap_mutex);
 }