arm64: dts: mediatek: mt2712e: Add mediatek, infracfg phandle for IOMMU

The IOMMU driver now looks for the "mediatek,infracfg" phandle as a
new way to retrieve a syscon to that:
even though the old way is retained, it has been deprecated and the
driver will write a message in kmsg advertising to use the phandle
way instead.

For this reason, assign the right phandle to mediatek,infracfg in
the iommu node.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Miles Chen <miles.chen@mediatek.com>
Link: https://lore.kernel.org/r/20220616110830.26037-5-angelogioacchino.delregno@collabora.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt2712e.dtsi

@@ -329,6 +329,7 @@ iommu0: iommu@10205000 {
 		interrupts = <GIC_SPI 147 IRQ_TYPE_LEVEL_LOW>;
 		clocks = <&infracfg CLK_INFRA_M4U>;
 		clock-names = "bclk";
+		mediatek,infracfg = <&infracfg>;
 		mediatek,larbs = <&larb0>, <&larb1>, <&larb2>,
 				 <&larb3>, <&larb6>;
 		#iommu-cells = <1>;
@@ -346,6 +347,7 @@ iommu1: iommu@1020a000 {
 		interrupts = <GIC_SPI 145 IRQ_TYPE_LEVEL_LOW>;
 		clocks = <&infracfg CLK_INFRA_M4U>;
 		clock-names = "bclk";
+		mediatek,infracfg = <&infracfg>;
 		mediatek,larbs = <&larb4>, <&larb5>, <&larb7>;
 		#iommu-cells = <1>;
 	};