net: pxa168_eth: set the mac address on the Ethernet controller

When changing the MAC address, in addition to updating the dev_addr in
the net_device structure, this patch also update the MAC address
registers (high and low) of the Ethernet controller with the new MAC.
The address stored in these registers is used for IEEE 802.3x Ethernet
flow control, which is already enabled.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>