scsi: qla2xxx: Fix duplicate switch database entries

The response data buffer used in switch scan is reused 4 times.  (For example,
for commands GPN_FT, GNN_FT for FCP and FC-NVME) Before driver reuses this
buffer, clear it to prevent duplicate entries in our database.

Fixes: a4239945 ("scsi: qla2xxx: Add switch command to simplify fabric discovery"
Cc: <stable@vger.kernel.org>
Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/qla2xxx/qla_gs.c

@@ -4193,9 +4193,9 @@ int qla24xx_async_gpnft(scsi_qla_host_t *vha, u8 fc4_type, srb_t *sp)
 	sp->u.iocb_cmd.timeout = qla2x00_async_iocb_timeout;
 	qla2x00_init_timer(sp, qla2x00_get_async_timeout(vha) + 2);
 
-	rspsz = sizeof(struct ct_sns_gpnft_rsp) +
-		((vha->hw->max_fibre_devices - 1) *
-		    sizeof(struct ct_sns_gpn_ft_data));
+	rspsz = sp->u.iocb_cmd.u.ctarg.rsp_size;
+	memset(sp->u.iocb_cmd.u.ctarg.rsp, 0, sp->u.iocb_cmd.u.ctarg.rsp_size);
+	memset(sp->u.iocb_cmd.u.ctarg.req, 0, sp->u.iocb_cmd.u.ctarg.req_size);
 
 	ct_sns = (struct ct_sns_pkt *)sp->u.iocb_cmd.u.ctarg.req;
 	/* CT_IU preamble  */