[SCSI] libfcoe: don't send ELS in FIP mode if no FCF selected

If link is up, but no FCF is selected, don't send any ELS frames.

This came up when an fnic received a multicast advertisement but
no solitited advertisments, so no FCF was selected.  It tried
to send FLOGIs anyway.

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>