inotify: Fix mask checks

The mask checks in inotify_update_existing_watch() and
inotify_new_watch() are useless because inotify_arg_to_mask() sets
FS_IN_IGNORED and FS_EVENT_ON_CHILD bits anyway.

Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index c8203ce..7dc940c 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -566,7 +566,7 @@
 
 	/* don't allow invalid bits: we don't want flags set */
 	mask = inotify_arg_to_mask(arg);
-	if (unlikely(!mask))
+	if (unlikely(!(mask & IN_ALL_EVENTS)))
 		return -EINVAL;
 
 	fsn_mark = fsnotify_find_inode_mark(group, inode);
@@ -624,7 +624,7 @@
 
 	/* don't allow invalid bits: we don't want flags set */
 	mask = inotify_arg_to_mask(arg);
-	if (unlikely(!mask))
+	if (unlikely(!(mask & IN_ALL_EVENTS)))
 		return -EINVAL;
 
 	tmp_i_mark = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);