arm64: dts: rockchip: drop #address-cells, #size-cells from rk3328 grf node

arm64: dts: rockchip: drop #address-cells, #size-cells from rk3328 grf node

The device tree compiler gives the following warning:

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

Since none of the grf node's direct child nodes have any reg properties,
remove the two properties from the grf node to silence the warning.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20200327030414.5903-5-wens@kernel.org
Signed-off-by: Heiko Stuebner <heiko@sntech.de>