qeth: exploit source MAC address for inbound layer3 packets

OSA-devices operating in layer3 mode offer adding of the source MAC
address to the QDIO header of inbound packets. The qeth driver can
exploit this functionality to replace FAKELL-entries in the ethernet
header of received packets.

Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>