* Phytium Display Engine

Required properties:
  - compatible : value should be "phytium,dc".
  - reg : first reg: Physical base address of the registers and length of memory
	  mapped region.
	  second reg (optional): Physical base address and length of video memory which is reserved system memory.
  - interrupts : interrupt number.
  - pipe_mask : specify which pipe is enabled, each bit corresponds to a pipe.
  - edp_mask : specify which pipe is edp port, each bit corresponds to a pipe (0:dp, 1:edp).

Example:
	/memreserve/ 0xf4000000 0x4000000; // (optional)

	dc0@32000000 {
		compatible = "phytium,dc";
		reg = <0x0 0x32000000 0x0 0x8000>,
		      <0x0 0xf4000000 0x0 0x4000000>; // (optional)
		interrupts = <GIC_SPI 44 IRQ_TYPE_LEVEL_HIGH>;
		pipe_mask = 0x3
		edp_mask = 0x0;
	};

