This reverts commit d1a08460.

From Al Viro:

"Rather bad way to do it - generally, register_filesystem() should be
the last thing done by initialization.  Any modular code that
does unregister_filesystem() on failure exit is flat-out broken;
here it's not instantly FUBAR, but it's a bloody bad example.

What's more, why not let simple_fill_super() do it?  Just
static int fill_super(struct super_block *sb, void *data, int silent)
{
        static const struct tree_descr files[] = {
                {"lsm", &lsm_ops, 0444},
                {""}
        };

and to hell with that call of securityfs_create_file() and all its
failure handling..."
Signed-off-by: James Morris <james.morris@microsoft.com>