autofs: fix error return in autofs_fill_super()

In autofs_fill_super() on error of get inode/make root dentry the return
should be ENOMEM as this is the only failure case of the called
functions.

Link: http://lkml.kernel.org/r/154725123240.11260.796773942606871359.stgit@pluto-themaw-netSigned-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/autofs/inode.c

@@ -266,8 +266,10 @@ int autofs_fill_super(struct super_block *s, void *data, int silent)
 	}
 	root_inode = autofs_get_inode(s, S_IFDIR | 0755);
 	root = d_make_root(root_inode);
-	if (!root)
+	if (!root) {
+		ret = -ENOMEM;
 		goto fail_ino;
+	}
 	pipe = NULL;
 
 	root->d_fsdata = ino;