scsi: lpfc: Honor module parameter lpfc_use_adisc

The initial lpfc_desc_set_adisc implementation in commit
dea3101e ("lpfc: add Emulex FC driver version 8.0.28") enabled ADISC if

	cfg_use_adisc && RSCN_MODE && FCP_2_DEVICE

In commit 92d7f7b0 ("[SCSI] lpfc: NPIV: add NPIV support on top of
SLI-3") this changed to

	(cfg_use_adisc && RSC_MODE) || FCP_2_DEVICE

and later in commit ffc95493 ("[SCSI] lpfc 8.3.13: FC Discovery Fixes
and enhancements.") to

	(cfg_use_adisc && RSC_MODE) || (FCP_2_DEVICE && FCP_TARGET)

A customer reports that after a devloss, an ADISC failure is logged. It
turns out the ADISC flag is set even the user explicitly set lpfc_use_adisc
= 0.

[Sat Dec 22 22:55:58 2018] lpfc 0000:82:00.0: 2:(0):0203 Devloss timeout on WWPN 50:01:43:80:12:8e:40:20 NPort x05df00 Data: x82000000 x8 xa
[Sat Dec 22 23:08:20 2018] lpfc 0000:82:00.0: 2:(0):2755 ADISC failure DID:05DF00 Status:x9/x70000

[mkp: fixed Hannes' email]

Fixes: 92d7f7b0 ("[SCSI] lpfc: NPIV: add NPIV support on top of SLI-3")
Cc: Dick Kennedy <dick.kennedy@broadcom.com>
Cc: James Smart <james.smart@broadcom.com>
Link: https://lore.kernel.org/r/20191022072112.132268-1-dwagner@suse.deReviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_nportdisc.c

@@ -851,9 +851,9 @@ lpfc_disc_set_adisc(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 
 	if (!(vport->fc_flag & FC_PT2PT)) {
 		/* Check config parameter use-adisc or FCP-2 */
-		if ((vport->cfg_use_adisc && (vport->fc_flag & FC_RSCN_MODE)) ||
+		if (vport->cfg_use_adisc && ((vport->fc_flag & FC_RSCN_MODE) ||
 		    ((ndlp->nlp_fcp_info & NLP_FCP_2_DEVICE) &&
-		     (ndlp->nlp_type & NLP_FCP_TARGET))) {
+		     (ndlp->nlp_type & NLP_FCP_TARGET)))) {
 			spin_lock_irq(shost->host_lock);
 			ndlp->nlp_flag |= NLP_NPR_ADISC;
 			spin_unlock_irq(shost->host_lock);