The gmac2phy is integrated with the PHY within the SoC. Any properties
related to this integration can be included in the .dtsi file, instead
of having board dts files specify them separately.

Add the clock_in_out property to specify the direction of the PHY clock.
This is the minimum required to have gmac2phy working on Linux. Other
examples include assigned-clocks, assigned-clock-rates, and
assigned-clock-parents properties, but the hardware default plus the
implementation requesting the appropriate clock rate also works.

Fixes: 9c4cc910 ("ARM64: dts: rockchip: Add gmac2phy node support for rk3328")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20210117100710.4857-2-wens@kernel.orgSigned-off-by: Heiko Stuebner <heiko@sntech.de>