Register a basic compat ioctl handler (32 vs 64 bit compat)
Simply pass the ioctl on to the normal handler. If the ioctl
helper macros are used correctly this should be safe as they
will handle the packing/unpacking of the data encoded in the
ioctl command. And actually, if the caller does not use the
IO* macros at all, and just passes small values, it will probably
be OK as well. We only get in to trouble if they try and use
the upper 32-bits. Endianness is not really a concern here, we
we are pretty much assumed they user and kernel will match.