ethernet: use eth_hw_addr_set() - casts

eth_hw_addr_set() takes a u8 pointer, like other
etherdevice helpers. Convert the few drivers which
require casts because they memcpy from "endian marked"
types.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>