scsi: core: Set shost as hctx driver_data

hctx->driver_data is not set for SCSI currently. Set hctx->driver_data =
shost.

Link: https://lore.kernel.org/r/20210215074048.19424-6-kashyap.desai@broadcom.com


Suggested-by: John Garry <john.garry@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>