[SCSI] libfc: RPN_ID is obsolete and unnecessary

RPN_ID has been obsolete per FC-GS-5 for several years.  The port name is
registered implicitly as part of FLOGI, and it is undesirable for ports to
change a registered port name using RPN_ID while logged into the fabric.

Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>