arm64: dts: qcom: ipq5018: add #clock-cells to GE Phy

arm64: dts: qcom: ipq5018: add #clock-cells to GE Phy

The IPQ5018 GE Phy driver registers two fixed rate clocks which are
passed on to the GCC which gatekeeps and passes them back to the phy.
Fix 'bad phandle' warning and tell consumer (GCC) how many cells to
expect when compiling.

Warning (clocks_property): /soc@0/clock-controller@1800000: Missing property '#clock-cells' in node /soc@0/mdio@88000/ethernet-phy@7 or bad phandle (referred from clocks[5])

Signed-off-by: George Moussalem <george.moussalem@outlook.com>
Link: https://github.com/openwrt/openwrt/pull/18548
Signed-off-by: Robert Marko <robimarko@gmail.com>