uli526x: fix endianness issues in the setup frame

This patch fixes uli526x driver's issues on a PowerPC boards: uli chip
is unable to receive the packets.

It appears that send_frame_filter prepares the setup frame in the
endianness unsafe manner. On a big endian machines we should shift
the address nibble by two bytes.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>