qeth: CCL-sequence numbers required for protocol ETH_P_802_2 only

Symptom:     slow CCL response time
Problem:     non-ETH_P_802_2 packets are not delivered to NDH for
             CCL. But CCL detects missing sequence numbers, which
             cause a serious performance problem with CCL.
Solution:    assign sequence numbers only to 802.2 packets.

Signed-off-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>