fsnotify: remove check that source dentry is positive

Remove the unneeded check for positive source dentry in
fsnotify_move().

fsnotify_move() hook is mostly called from vfs_rename() under
lock_rename() and vfs_rename() starts with may_delete() test that
verifies positive source dentry.  The only other caller of
fsnotify_move() - debugfs_rename() also verifies positive source.

Link: https://lore.kernel.org/r/20200716084230.30611-17-amir73il@gmail.comSigned-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

include/linux/fsnotify.h

@@ -150,9 +150,7 @@ static inline void fsnotify_move(struct inode *old_dir, struct inode *new_dir,
 
 	if (target)
 		fsnotify_link_count(target);
-
-	if (source)
-		fsnotify_inode(source, FS_MOVE_SELF);
+	fsnotify_inode(source, FS_MOVE_SELF);
 	audit_inode_child(new_dir, moved, AUDIT_TYPE_CHILD_CREATE);
 }