include: Convert ethernet mac address declarations to use ETH_ALEN

It's convenient to have ethernet mac addresses use
ETH_ALEN to be able to grep for them a bit easier and
also to ensure that the addresses are __aligned(2).

Add #include <linux/if_ether.h> as necessary.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: David S. Miller <davem@davemloft.net>