fscache: add missing unlock

Sparse complained about this missing spin_unlock()

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/fscache/page.c b/fs/fscache/page.c
index c598ea4..6980902 100644
--- a/fs/fscache/page.c
+++ b/fs/fscache/page.c
@@ -881,6 +881,7 @@
 	goto nobufs;
 
 nobufs_unlock_obj:
+	spin_unlock(&cookie->stores_lock);
 	spin_unlock(&object->lock);
 nobufs:
 	spin_unlock(&cookie->lock);