* HGSL

HGSL(Hypervisor Graphics system layer) is graphics driver under the hypervisor system.

Required properties:
- compatible : Must be "qcom,hgsl"

- reg : physical base address and length of the register set(s).

- reg-names : names corresponding to each reg property value.
	      reg_hwver: HW version registers
	      reg_doorbell_idx: address of GMUAO_DOORBELL_IDX

Optional properties:
- db-off: Disable Doorbell feature but keep hgsl for ifence service
- qcom,glb-db-senders : Point to possible nodes of HGSL TCSR sender. The user will select
		        which sender to use. The driver will use TCSR compute signal to
		        send signal to GPU.
- qcom,glb-db-receivers : Point to possible nodes of HGSL TCSR receiver. The user will
			  select which receiver to use. The driver will use TCSR compute
			  signal to receive signal from GPU.

Example:
	msm_gpu_hyp {
		compatible = "qcom,hgsl";
		reg = <0x2c00000 0x8>, <0x2c8f000 0x4>;
		reg-names = "hgsl_reg_hwinf", "hgsl_reg_gmucx";

		db-off = <0>;
		qcom,glb-db-senders = <&hgsl_tcsr_sender0 &hgsl_tcsr_sender1>;
		qcom,glb-db-receivers = <&hgsl_tcsr_receiver0 &hgsl_tcsr_receiver1>;
	};