scsi: qla2xxx: Use scsi_cmd_to_rq() instead of scsi_cmnd.request

[ Upstream commit c7d6b2c2

 ]

Prepare for removal of the request pointer by using scsi_cmd_to_rq()
instead. This patch does not change any functionality.

Link: https://lore.kernel.org/r/20210809230355.8186-39-bvanassche@acm.org
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Stable-dep-of: 19597cad

 ("scsi: qla2xxx: Fix system crash due to bad pointer access")
Signed-off-by: Sasha Levin <sashal@kernel.org>