[SCSI] libfc: clean up point-to-point discovery code.

The discovery code had a special-case for the point-to-point mode,
which used a bunch of code that wasn't really needed.

Now that rport_create adds the rport to the discovery list,
completely skip discovery for the point-to-point case.

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>