[SCSI] libfcoe: Fix FIP ELS encapsulation details for FLOGI responses

When sending a FLOGI LS_ACC, which we only do in point-to-multipoint
mode, the MAC descriptor should have the granted MAC set to
0x0efd00 || D_ID.

When sending an LS_RJT, there should be no MAC descriptor.

When sending either an LS_ACC or LS_RJT, the subcode should indicate
an reply, not a request.

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>