scsi: lpfc: Fix pt2pt state transition causing rmmod hang

On a setup with a dual port HBA and both ports direct connected, an rmmod
hangs momentarily when we log an Illegal State Transition. Once it resumes,
a nodelist not empty logic is hit, which forces rmmod to cleanup and exit.
We're missing a state transition case in the discovery engine.

Fix by adding a case for a DEVICE_RM event while in the unmapped state to
avoid illegal state transition log message.

Link: https://lore.kernel.org/r/20210301171821.3427-17-jsmart2021@gmail.comCo-developed-by: Dick Kennedy <dick.kennedy@broadcom.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_nportdisc.c

@@ -2485,6 +2485,16 @@ lpfc_rcv_prlo_unmap_node(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 	return ndlp->nlp_state;
 }
 
+static uint32_t
+lpfc_device_rm_unmap_node(struct lpfc_vport *vport,
+			  struct lpfc_nodelist *ndlp,
+			  void *arg,
+			  uint32_t evt)
+{
+	lpfc_drop_node(vport, ndlp);
+	return NLP_STE_FREED_NODE;
+}
+
 static uint32_t
 lpfc_device_recov_unmap_node(struct lpfc_vport *vport,
 			     struct lpfc_nodelist *ndlp,
@@ -2978,7 +2988,7 @@ static uint32_t (*lpfc_disc_action[NLP_STE_MAX_STATE * NLP_EVT_MAX_EVENT])
 	lpfc_disc_illegal,		/* CMPL_LOGO       */
 	lpfc_disc_illegal,		/* CMPL_ADISC      */
 	lpfc_disc_illegal,		/* CMPL_REG_LOGIN  */
-	lpfc_disc_illegal,		/* DEVICE_RM       */
+	lpfc_device_rm_unmap_node,	/* DEVICE_RM       */
 	lpfc_device_recov_unmap_node,	/* DEVICE_RECOVERY */
 
 	lpfc_rcv_plogi_mapped_node,	/* RCV_PLOGI   MAPPED_NODE    */