Device-Tree bindings for Mediatek random number generator
found in Mediatek SoC family

Required properties:
- compatible	    : Should be
			"mediatek,mt7622-rng", "mediatek,mt7623-rng" for MT7622
			"mediatek,mt7623-rng" for MT7623
			"mediatek,mt67xx-rng" for MT67xx ARMv8 SoCs

Optional properties:
- clocks	    : list of clock specifiers, corresponding to
		      entries in clock-names property;
- clock-names	    : Should contain "rng" entries;
- reg 		    : Specifies base physical address and size of the registers

Example:

rng: rng@1020f000 {
	compatible = "mediatek,mt7623-rng";
	reg = <0 0x1020f000 0 0x1000>;
	clocks = <&infracfg CLK_INFRA_TRNG>;
	clock-names = "rng";
};

hwrng: hwrng {
	compatible = "mediatek,mt67xx-rng";
};