arm64: dts: mt8173: add mmsel clocks for 4K support

To support HDMI 4K resolution, mmsys need clcok
mm_sel to be 400MHz.

The board .dts file should override the clock rate
property with the higher VENCPLL frequency the board
supports HDMI 4K resolution.
Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt8173.dtsi

@@ -778,6 +778,8 @@ mmsys: clock-controller@14000000 {
 			compatible = "mediatek,mt8173-mmsys", "syscon";
 			reg = <0 0x14000000 0 0x1000>;
 			power-domains = <&scpsys MT8173_POWER_DOMAIN_MM>;
+			assigned-clocks = <&topckgen CLK_TOP_MM_SEL>;
+			assigned-clock-rates = <400000000>;
 			#clock-cells = <1>;
 		};