[SCSI] libfc: Make the libfc Common Transport(CT) code generic

Currently the libfc Common Transport(CT) calls assume that
the CT requests are Name Server specific only. This patch
makes it more flexible to allow more FC-GS services to make
use of these routines.

Signed-off-by: Neerav Parikh <neerav.parikh@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Acked-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>