[SCSI] libfcoe: Move FCOE_MTU definition from fcoe.h to libfcoe.h

both fcoe and bnx2fc drivers can access the common definition of
FCOE_MTU.

Signed-off-by: Bhanu Prakash Gollapudi <bprakash@broadcom.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/libfcoe.h b/include/scsi/libfcoe.h
index e502463..8c1638b 100644
--- a/include/scsi/libfcoe.h
+++ b/include/scsi/libfcoe.h
@@ -33,6 +33,12 @@
 #define FCOE_MAX_CMD_LEN	16	/* Supported CDB length */
 
 /*
+ * Max MTU for FCoE: 14 (FCoE header) + 24 (FC header) + 2112 (max FC payload)
+ * + 4 (FC CRC) + 4 (FCoE trailer) =  2158 bytes
+ */
+#define FCOE_MTU	2158
+
+/*
  * FIP tunable parameters.
  */
 #define FCOE_CTLR_START_DELAY	2000	/* mS after first adv. to choose FCF */