The Aspeed System Control Unit manages the global behaviour of the SoC,
configuring elements such as clocks, pinmux, and reset.

Required properties:
- compatible:	One of:
		"aspeed,ast2400-scu", "syscon", "simple-mfd"
		"aspeed,ast2500-scu", "syscon", "simple-mfd"

- reg:		contains the offset and length of the SCU memory region
- #clock-cells: should be set to <1> - the system controller is also a
	clock provider
- #reset-cells: should be set to <1> - the system controller is also a
	reset line provider

Example:

syscon: syscon@1e6e2000 {
	compatible = "aspeed,ast2400-scu", "syscon", "simple-mfd";
	reg = <0x1e6e2000 0x1a8>;
	#clock-cells = <1>;
	#reset-cells = <1>;
};

Silicon ID
-----------------

Families have unique hardware silicon identifiers within the SoC.

Required properties:

 - compatible:		"aspeed,silicon-id" or:
			"aspeed,ast2400-silicon-id" or
			"aspeed,ast2500-silicon-id" or
			"aspeed,ast2600-silicon-id"

 - reg:			offset and length of the silicon id information
			optionally, a second offset and length describes the unique chip id

			The reg should be the unique silicon id register, and
			not backwards compatible one in eg. the 2600.

Example:


silicon-id@7c {
        compatible = "aspeed,ast2500-silicon-id", "aspeed,silicon-id";
        reg = <0x7c 0x4 0x150 0x8>;
};