net: stmmac: Integrate it with DesignWare XPCS

Adds all the necessary logic so that stmmac can be used with Synopsys
DesignWare XPCS.

Signed-off-by: Jose Abreu <Jose.Abreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
6 files changed