As of linux-2.6.36 the last in-tree consumer of fops->ioctl() has
been removed and thus fops()->ioctl() has also been removed. The
replacement hook is fops->unlocked_ioctl() which has existed in
kernel since 2.6.12. Since the SPL only contains support back
to 2.6.18 vintage kernels, I'm not adding an autoconf check for
this and simply moving everything to use fops->unlocked_ioctl().