Top Control and Status Register(TCSR) for HGSL

TCSR hardware contains compute signal sub-block, which allows drivers in hypervisor
Linux to communicate with GPU hardware directly. This HGSL TCSR driver is to enable
the TCSR compute signal hardware. There are multiple instances of compute signal.
Each instance is either a signal sender or signal receiver.

The HGSL TCSR driver is built on top of generic TCSR driver, refer to
Documentation/devicetree/bindings/mfd/qcom,tcsr.txt for the generic TCSR driver.

Required properties:
- compatible : Must be "qcom,hgsl-tcsr-sender" or "qcom,hgsl-tcsr-receiver"
- syscon     : Point to the generic TCSR compute signal node
- syscon-glb : Point to the generice TCSR node for compute signal global control.
	       This is only needed by signal sender.
- interrupts : Specify IRQ information used by the compute signal.
	       This is only needed by signal receiver.

Examples:
	hgsl_tcsr_sender0: hgsl_tcsr_sender0 {
		compatible = "qcom,hgsl-tcsr-sender";
		syscon = <&tcsr_compute_signal_sender0>;
		syscon-glb = <&tcsr_compute_signal_glb>;
	};

	hgsl_tcsr_receiver0: hgsl_tcsr_receiver0 {
		compatible = "qcom,hgsl-tcsr-receiver";
		syscon = <&tcsr_compute_signal_receiver0>;
		interrupts = <0 238 0>;
	};

