lcs: CCL-sequ. numbers required for protocol 802.2 only.

Sequence numbers in skbs (Receive path) are assigned only to
802.2 packets.

Signed-off-by: Klaus D. Wacker <kdwacker@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>