scsi: lpfc: fix: Coverity: lpfc_cmpl_els_rsp(): Null pointer dereferences

Coverity reported the following:

*** CID 101747:  Null pointer dereferences  (FORWARD_NULL)
/drivers/scsi/lpfc/lpfc_els.c: 4439 in lpfc_cmpl_els_rsp()
4433     			kfree(mp);
4434     		}
4435     		mempool_free(mbox, phba->mbox_mem_pool);
4436     	}
4437     out:
4438     	if (ndlp && NLP_CHK_NODE_ACT(ndlp)) {
vvv     CID 101747:  Null pointer dereferences  (FORWARD_NULL)
vvv     Dereferencing null pointer "shost".
4439     		spin_lock_irq(shost->host_lock);
4440     		ndlp->nlp_flag &= ~(NLP_ACC_REGLOGIN | NLP_RM_DFLT_RPI);
4441     		spin_unlock_irq(shost->host_lock);
4442
4443     		/* If the node is not being used by another discovery thread,
4444     		 * and we are sending a reject, we are done with it.

Fix by adding a check for non-null shost in line 4438.
The scenario when shost is set to null is when ndlp is null.
As such, the ndlp check present was sufficient. But better safe
than sorry so add the shost check.
Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 101747 ("Null pointer dereferences")
Fixes: 2e0fef85 ("[SCSI] lpfc: NPIV: split ports")

CC: James Bottomley <James.Bottomley@SteelEye.com>
CC: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
CC: linux-next@vger.kernel.org
Link: https://lore.kernel.org/r/20191111230401.12958-3-jsmart2021@gmail.comReviewed-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_els.c

@@ -4445,7 +4445,7 @@ lpfc_cmpl_els_rsp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
 		mempool_free(mbox, phba->mbox_mem_pool);
 	}
 out:
-	if (ndlp && NLP_CHK_NODE_ACT(ndlp)) {
+	if (ndlp && NLP_CHK_NODE_ACT(ndlp) && shost) {
 		spin_lock_irq(shost->host_lock);
 		ndlp->nlp_flag &= ~(NLP_ACC_REGLOGIN | NLP_RM_DFLT_RPI);
 		spin_unlock_irq(shost->host_lock);