net: fec: phy-reset-gpios is optional

The phy-reset-gpios is an optional property for fec device tree boot.
Change the binding document to match the driver code.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed