arm64: dts: rockchip: drop #address-cells, #size-cells from rk3399 pmugrf node

The device tree compiler gives the following warning:

    /syscon@ff100000: unnecessary #address-cells/#size-cells without
    "ranges" or child "reg" property

Since the pmygrf node only has an io-domains child node that has no
reg property, remove the two properties from the pmugrf node to silence
the warning.
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20200327030414.5903-6-wens@kernel.orgSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399.dtsi

@@ -1124,8 +1124,6 @@ pd_vopl@RK3399_PD_VOPL {
 	pmugrf: syscon@ff320000 {
 		compatible = "rockchip,rk3399-pmugrf", "syscon", "simple-mfd";
 		reg = <0x0 0xff320000 0x0 0x1000>;
-		#address-cells = <1>;
-		#size-cells = <1>;
 
 		pmu_io_domains: io-domains {
 			compatible = "rockchip,rk3399-pmu-io-voltage-domain";