gianfar v5: implement nfc

This patch adds all missing functionalities for nfc except GRXFH. There is so much code because hardware has not a TCAM.
Further hardware rule space is very limited. So I had to extensively use
optimization features. Both reasons lead to the necessity to hold all
online flows in a linked-list.

Change-log:
# Some suggestions by Joe Perches applied (thanks!)
# Shorted some logs
# Use memcmp() for comparing

Signed-off-by: Sebastian Poehn <sebastian.poehn@belden.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc drivers/net/gianfar.c
Simple merge

diff --cc drivers/net/gianfar.h
Simple merge

diff --cc drivers/net/gianfar_ethtool.c
Simple merge