SMI (Smart Multimedia Interface) Local Arbiter

The hardware block diagram please check bindings/iommu/mediatek,iommu.txt

Required properties:
- compatible : must be one of :
		"mediatek,mt8173-smi-larb"
		"mediatek,mt2701-smi-larb"
- reg : the register and size of this local arbiter.
- mediatek,smi : a phandle to the smi_common node.
- power-domains : a phandle to the power domain of this local arbiter.
- clocks : Must contain an entry for each entry in clock-names.
- clock-names: must contain 2 entries, as follows:
  - "apb" : Advanced Peripheral Bus clock, It's the clock for setting
	    the register.
  - "smi" : It's the clock for transfer data and command.

Example:
	larb1: larb@16010000 {
		compatible = "mediatek,mt8173-smi-larb";
		reg = <0 0x16010000 0 0x1000>;
		mediatek,smi = <&smi_common>;
		power-domains = <&scpsys MT8173_POWER_DOMAIN_VDEC>;
		clocks = <&vdecsys CLK_VDEC_CKEN>,
			 <&vdecsys CLK_VDEC_LARB_CKEN>;
		clock-names = "apb", "smi";
	};