[SCSI] libfc: fix: empty zone causes endless discovery retries.

On some switches, an empty zone causes GPN_FT to be rejected
with reason 9 (unable) explanation 7 (FC-4 types not registered),
which causes discovery to be retried endlessly.  Treat this as
just an empty response and consider discovery complete.

Signed-off-by: Joe Eykholt <jeykholt@cisco.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/fc/fc_gs.h b/include/scsi/fc/fc_gs.h
index ffab027..324dd0e 100644
--- a/include/scsi/fc/fc_gs.h
+++ b/include/scsi/fc/fc_gs.h
@@ -87,6 +87,7 @@
 	FC_FS_EXP_PNAM =	0x02,	/* port name not registered */
 	FC_FS_EXP_NNAM =	0x03,	/* node name not registered */
 	FC_FS_EXP_COS =		0x04,	/* class of service not registered */
+	FC_FS_EXP_FTNR =	0x07,	/* FC-4 types not registered */
 	/* definitions not complete */
 };