[SCSI] lpfc 8.1.7: Add lpfc_sli_flush_mbox_queue() function

Add lpfc_sli_flush_mbox_queue() function and use it in lpfc_offline() call
to avoid deadlock on thread block.

Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/lpfc/lpfc_crtn.h b/drivers/scsi/lpfc/lpfc_crtn.h
index ee22173..517e9e4 100644
--- a/drivers/scsi/lpfc/lpfc_crtn.h
+++ b/drivers/scsi/lpfc/lpfc_crtn.h
@@ -147,6 +147,7 @@
 int lpfc_sli_hba_down(struct lpfc_hba *);
 int lpfc_sli_issue_mbox(struct lpfc_hba *, LPFC_MBOXQ_t *, uint32_t);
 int lpfc_sli_handle_mb_event(struct lpfc_hba *);
+int lpfc_sli_flush_mbox_queue(struct lpfc_hba *);
 int lpfc_sli_handle_slow_ring_event(struct lpfc_hba *,
 				    struct lpfc_sli_ring *, uint32_t);
 void lpfc_sli_def_mbox_cmpl(struct lpfc_hba *, LPFC_MBOXQ_t *);