This allows 32-bit userspace tools (tw_cli, smartctl) to work on a
64-bit system.  The command buffer is opaque to us, so, no word size
problems.
Signed-off-by: Ryan C. Underwood <nemesis@icequake.net>
Reviewed-by: Shane Seymour <shane.seymour@hpe.com>
Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>