wireless: Use eth_random_addr

Convert the existing uses of random_ether_addr to
the new eth_random_addr.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>