net: dpaa: Convert to phylink

This converts DPAA to phylink. All macs are converted. This should work
with no device tree modifications (including those made in this series),
except for QSGMII (as noted previously).

The mEMAC configuration is one of the tricker areas. I have tried to
capture all the restrictions across the various models. Most of the time,
we assume that if the serdes supports a mode or the phy-interface-mode
specifies it, then we support it. The only place we can't do this is
(RG)MII, since there's no serdes. In that case, we rely on a (new)
devicetree property. There are also several cases where half-duplex is
broken. Unfortunately, only a single compatible is used for the MAC, so we
have to use the board compatible instead.

The 10GEC conversion is very straightforward, since it only supports XAUI.
There is generally nothing to configure.

The dTSEC conversion is broadly similar to mEMAC, but is simpler because we
don't support configuring the SerDes (though this can be easily added) and
we don't have multiple PCSs. From what I can tell, there's nothing
different in the driver or documentation between SGMII and 1000BASE-X
except for the advertising. Similarly, I couldn't find anything about
2500BASE-X. In both cases, I treat them like SGMII. These modes aren't used
by any in-tree boards. Similarly, despite being mentioned in the driver, I
couldn't find any documented SoCs which supported QSGMII.  I have left it
unimplemented for now.

Signed-off-by: Sean Anderson <sean.anderson@seco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>