stmmac: remove unused stmmac_of_data struct

As dwmac-* drivers that need OF match have been converted
to use their own internal OF match data structure this can
now be removed.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc Documentation/networking/stmmac.txt
Simple merge

diff --cc include/linux/stmmac.h
Simple merge