omfs: set error return when d_make_root() fails

A static checker found the following issue in the error path for
omfs_fill_super:

    fs/omfs/inode.c:552 omfs_fill_super()
    warn: missing error code here? 'd_make_root()' failed. 'ret' = '0'

Fix by returning -ENOMEM in this case.
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/omfs/inode.c

@@ -549,8 +549,10 @@ static int omfs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	sb->s_root = d_make_root(root);
-	if (!sb->s_root)
+	if (!sb->s_root) {
+		ret = -ENOMEM;
 		goto out_brelse_bh2;
+	}
 	printk(KERN_DEBUG "omfs: Mounted volume %s\n", omfs_rb->r_name);
 
 	ret = 0;