AT91RM9200 Ethernet: Fix multicast addressing

The order that the two 32-bit words written to the Hash Address (Low,
High) Registers for matching of multicast addresses is incorrect.

Signed-off-by: Lars Reemts <Lars.Reemts@entwicklung.eq-3.de>
Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>