This patch adds to support the emac phy reset.
1) phy-reset-gpios:
The phy-reset-gpios is an optional property for arc emac device tree boot.
Change the binding document to match the driver code.
2) phy-reset-duration:
Different boards may require different phy reset duration. Add property
phy-reset-duration for device tree probe, so that the boards that need
a longer reset duration can specify it in their device tree.
3) phy-reset-active-high:
We need that for a custom hardware that needs the reverse reset sequence.
Of course, this patch will fix the issue on
https://patchwork.kernel.org/patch/8186801/.
In some cases, the emac couldn't work if you don't have reset the phy.
Let's add it to happy work.
Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx>