A quick survey for the of_get_mac_address users learns that most of them do
a memcpy (or similar) right after it, so for these drivers the
"of_get_nvmem_mac_address" style signature that performs the memcpy (or
better, ether_addr_copy) is a better fit, e.g.:

int of_get_mac_address(struct device_node *np, void *addr)

Hi Mike

This is a nicer solution, but it is quite a lot of work, there are a
lot of users. Maybe Coccinelle can help?

    Andrew