net: lpc_eth: Fix rename of dev_hw_addr_random

In parallel to the integration of lpc_eth.c, dev_hw_addr_random() has been
renamed to eth_hw_addr_random(). This patch fixes it also in the new driver
lpc_eth.c.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: David S. Miller <davem@davemloft.net>