scsi: lpfc: lpfc_nportdisc: Mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>

drivers/scsi/lpfc/lpfc_nportdisc.c

@@ -360,6 +360,7 @@ lpfc_rcv_plogi(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp,
 	case  NLP_STE_NPR_NODE:
 		if (!(ndlp->nlp_flag & NLP_NPR_ADISC))
 			break;
+		/* fall through */
 	case  NLP_STE_REG_LOGIN_ISSUE:
 	case  NLP_STE_PRLI_ISSUE:
 	case  NLP_STE_UNMAPPED_NODE: