scsi: core: Remove the sense and sense_len fields from struct scsi_request

Just use the sense_buffer field in struct scsi_cmnd for the sense data and
move the sense_len field over to struct scsi_cmnd.

Link: https://lore.kernel.org/r/20220224175552.988286-5-hch@lst.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>