Merge branch 'stmmac-rk3368'

Heiko Stuebner says:

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net: stmmac: dwmac-rk: add support for rk3368

Apart from small cleanups, this series provides support for the dwmac
on the new rk3368 ARM64 soc.

Tested on a R88 board using a RMII phy.

Changes since v1:
- Adapt to changes resulting from patch d42202dc ("net: stmmac:
dwmac-rk: Don't add function name in info or err messages")
====================

Signed-off-by: David S. Miller <davem@davemloft.net>