[SCSI] aic7xxx_old, eata_pio, ips, libsas: don't zero out sense_buffer in queuecommand

LLDs don't need to zero out scsi_cmnd::sense_buffer in queuecommand
since scsi-ml does. This is a preparation of the future changes to
allocate the sense_buffer only when necessary.

Many LLDs zero out the sense_buffer before touching it on the error
case. This patch lets them alone for now because new APIs for them
would be added later on.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: "Salyzyn, Mark" <Mark_Salyzyn@adaptec.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/aic7xxx_old.c

@@ -10293,7 +10293,6 @@ static int aic7xxx_queue(struct scsi_cmnd *cmd, void (*fn)(struct scsi_cmnd *))
   aic7xxx_position(cmd) = scb->hscb->tag;
   cmd->scsi_done = fn;
   cmd->result = DID_OK;
-  memset(cmd->sense_buffer, 0, sizeof(cmd->sense_buffer));
   aic7xxx_error(cmd) = DID_OK;
   aic7xxx_status(cmd) = 0;
   cmd->host_scribble = NULL;