[SCSI] fcoe libfcoe: use correct FC-MAP for VN2VN mode

In VN2VN mode, map_dest means to use the default VN2VN OUI.
Change code that uses the default FCoE OUI to use the one
set in the fcoe_ctlr struct.

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>