[SCSI] fcoe, libfc: add get_lesb() to allow LLD to fill the link error status block (LESB)

Add a member function pointer as get_lesb to libfc_function_template so LLD
can fill the LESB based on its own statistics. For fcoe, it fills the LESB
as a fcoe_fc_els_lesb struct according to FC-BB-5.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h
index b97be29..4b912ee 100644
--- a/include/scsi/libfc.h
+++ b/include/scsi/libfc.h
@@ -511,6 +511,12 @@
 	 */
 	int (*ddp_done)(struct fc_lport *, u16);
 	/*
+	 * Allow LLD to fill its own Link Error Status Block
+	 *
+	 * STATUS: OPTIONAL
+	 */
+	void (*get_lesb)(struct fc_lport *, struct fc_els_lesb *lesb);
+	/*
 	 * Send a frame using an existing sequence and exchange.
 	 *
 	 * STATUS: OPTIONAL