scsi: bnx2i: missing error code in bnx2i_ep_connect()

If bnx2i_map_ep_dbell_regs() then we accidentally return NULL instead of
an error pointer.  It results in a NULL dereference in
iscsi_if_ep_connect().

Fixes: cf4e6363859d ("[SCSI] bnx2i: Add bnx2i iSCSI driver.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/bnx2i/bnx2i_iscsi.c

@@ -1909,7 +1909,8 @@ static struct iscsi_endpoint *bnx2i_ep_connect(struct Scsi_Host *shost,
 
 	bnx2i_ep_active_list_add(hba, bnx2i_ep);
 
-	if (bnx2i_map_ep_dbell_regs(bnx2i_ep))
+	rc = bnx2i_map_ep_dbell_regs(bnx2i_ep);
+	if (rc)
 		goto del_active_ep;
 
 	mutex_unlock(&hba->net_dev_lock);