[SCSI] libfcoe: retry rejected FLOGI to another FCF if possible

Switches using multiple-FCFs may reject FLOGI in order to
balance the load between multiple FCFs.  Even though the FCF
was available, it may have more load at the point we actually
send the FLOGI.

If the FLOGI fails, select a different FCF
if possible, among those with the same priority.  If no other
FCF is available, just deliver the reject to libfc for retry.

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>