scsi: fcoe: remove redundant call to skb_transport_header

Pointer fh is being assigned a return value from the call to
skb_transport_header however this value is never read and fh is being
re-assigned immediately afterwards with a new value.  Since there are
side-effects from calling skb_transport_header the call is redundant and
can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>