net: add Faraday FTMAC100 10/100 Ethernet driver

FTMAC100 Ethernet Media Access Controller supports 10/100 Mbps and
MII.  This driver has been working on some ARM/NDS32 SoC's including
Faraday A320 and Andes AG101.

Signed-off-by: Po-Yu Chuang <ratbert@faraday-tech.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>