Drop the internal SCSI message definitions and use the functions provided
by the SPI transport class.

Link: https://lore.kernel.org/r/20210113090500.129644-21-hare@suse.deReported-by: Nkernel test robot <lkp@intel.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>