scsi: 53c700: Stop clearing SCSI pointer fields

None of the 53c700 drivers uses the SCSI pointer. Hence remove the code
from 53c700.c that clears two SCSI pointer fields. The 53c700 drivers are:

$ git grep -l 'include.*53c700'
drivers/scsi/53c700.c
drivers/scsi/a4000t.c
drivers/scsi/bvme6000_scsi.c
drivers/scsi/lasi700.c
drivers/scsi/mvme16x_scsi.c
drivers/scsi/sim710.c
drivers/scsi/sni_53c710.c
drivers/scsi/zorro7xx.c

Link: https://lore.kernel.org/r/20220218195117.25689-12-bvanassche@acm.org
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/53c700.c

@@ -1791,8 +1791,6 @@ static int NCR_700_queuecommand_lck(struct scsi_cmnd *SCp)
 	slot->cmnd = SCp;
 
 	SCp->host_scribble = (unsigned char *)slot;
-	SCp->SCp.ptr = NULL;
-	SCp->SCp.buffer = NULL;
 
 #ifdef NCR_700_DEBUG
 	printk("53c700: scsi%d, command ", SCp->device->host->host_no);