scsi: lpfc: Address NULL pointer dereference after starget_to_rport()

Calls to starget_to_rport() may return NULL.  Add check for NULL rport
before dereference.

Link: https://lore.kernel.org/r/20220603174329.63777-5-jsmart2021@gmail.com
Fixes: bb21fc9 ("scsi: lpfc: Use fc_block_rport()")
Cc: <stable@vger.kernel.org> # v5.18
Co-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_scsi.c

@@ -6062,6 +6062,9 @@ lpfc_device_reset_handler(struct scsi_cmnd *cmnd)
 	int status;
 	u32 logit = LOG_FCP;
 
+	if (!rport)
+		return FAILED;
+
 	rdata = rport->dd_data;
 	if (!rdata || !rdata->pnode) {
 		lpfc_printf_vlog(vport, KERN_ERR, LOG_TRACE_EVENT,
@@ -6140,6 +6143,9 @@ lpfc_target_reset_handler(struct scsi_cmnd *cmnd)
 	unsigned long flags;
 	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(waitq);
 
+	if (!rport)
+		return FAILED;
+
 	rdata = rport->dd_data;
 	if (!rdata || !rdata->pnode) {
 		lpfc_printf_vlog(vport, KERN_ERR, LOG_TRACE_EVENT,