Qualcomm adreno/snapdragon GPU

Required properties:
- compatible: "qcom,adreno-3xx"
- reg: Physical base address and length of the controller's registers.
- interrupts: The interrupt signal from the gpu.
- clocks: device clocks
  See ../clocks/clock-bindings.txt for details.
- clock-names: the following clocks are required:
  * "core_clk"
  * "iface_clk"
  * "mem_iface_clk"
- qcom,chipid: gpu chip-id.  Note this may become optional for future
  devices if we can reliably read the chipid from hw
- qcom,gpu-pwrlevels: list of operating points
  - compatible: "qcom,gpu-pwrlevels"
  - for each qcom,gpu-pwrlevel:
    - qcom,gpu-freq: requested gpu clock speed
    - NOTE: downstream android driver defines additional parameters to
      configure memory bandwidth scaling per OPP.

Example:

/ {
	...

	gpu: qcom,kgsl-3d0@4300000 {
		compatible = "qcom,adreno-3xx";
		reg = <0x04300000 0x20000>;
		reg-names = "kgsl_3d0_reg_memory";
		interrupts = <GIC_SPI 80 0>;
		interrupt-names = "kgsl_3d0_irq";
		clock-names =
		    "core_clk",
		    "iface_clk",
		    "mem_iface_clk";
		clocks =
		    <&mmcc GFX3D_CLK>,
		    <&mmcc GFX3D_AHB_CLK>,
		    <&mmcc MMSS_IMEM_AHB_CLK>;
		qcom,chipid = <0x03020100>;
		qcom,gpu-pwrlevels {
			compatible = "qcom,gpu-pwrlevels";
			qcom,gpu-pwrlevel@0 {
				qcom,gpu-freq = <450000000>;
			};
			qcom,gpu-pwrlevel@1 {
				qcom,gpu-freq = <27000000>;
			};
		};
	};
};
