scsi: remove the gendisk argument to scsi_ioctl

scsi: remove the gendisk argument to scsi_ioctl

Now that blk_execute_rq does not take a gendisk argument there is no need
to pass it through the scsi_ioctl callchain either.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20211126121802.2090656-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>