nilfs2: unbreak compat ioctl

commit 695c60f2 upstream.

commit 828b1c50 ("nilfs2: add compat ioctl") incidentally broke all
other NILFS compat ioctls.  Make them work again.

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>