Aspeed Vectored Interrupt Controller

These bindings are for the Aspeed interrupt controller. The AST2400 and
AST2500 SoC families include a legacy register layout before a re-designed
layout, but the bindings do not prescribe the use of one or the other.

Required properties:

- compatible : "aspeed,ast2400-vic"
               "aspeed,ast2500-vic"

- interrupt-controller : Identifies the node as an interrupt controller
- #interrupt-cells : Specifies the number of cells needed to encode an
  interrupt source. The value shall be 1.

Example:

 vic: interrupt-controller@1e6c0080 {
      compatible = "aspeed,ast2400-vic";
      interrupt-controller;
      #interrupt-cells = <1>;
      reg = <0x1e6c0080 0x80>;
 };
