dt-bindings: clock: Introduce QCOM Graphics clock bindings

Add device tree bindings for graphics clock controller for
Qualcomm Technology Inc's SDM845 SoCs.
Signed-off-by: Amit Nischal <anischal@codeaurora.org>
Reviewed-by: Rob Herring <robh@kernel.org>
[sboyd@kernel.org: Add input clocks property]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Documentation/devicetree/bindings/clock/qcom,gpucc.txt

+Qualcomm Graphics Clock & Reset Controller Binding
+--------------------------------------------------
+
+Required properties :
+- compatible : shall contain "qcom,sdm845-gpucc"
+- reg : shall contain base register location and length
+- #clock-cells : from common clock binding, shall contain 1
+- #reset-cells : from common reset binding, shall contain 1
+- #power-domain-cells : from generic power domain binding, shall contain 1
+- clocks : shall contain the XO clock
+- clock-names : shall be "xo"
+
+Example:
+	gpucc: clock-controller@5090000 {
+		compatible = "qcom,sdm845-gpucc";
+		reg = <0x5090000 0x9000>;
+		#clock-cells = <1>;
+		#reset-cells = <1>;
+		#power-domain-cells = <1>;
+		clocks = <&xo_board>;
+		clock-names = "xo";
+	};

include/dt-bindings/clock/qcom,gpucc-sdm845.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2018, The Linux Foundation. All rights reserved.
+ */
+
+#ifndef _DT_BINDINGS_CLK_SDM_GPU_CC_SDM845_H
+#define _DT_BINDINGS_CLK_SDM_GPU_CC_SDM845_H
+
+/* GPU_CC clock registers */
+#define GPU_CC_CX_GMU_CLK			0
+#define GPU_CC_CXO_CLK				1
+#define GPU_CC_GMU_CLK_SRC			2
+#define GPU_CC_PLL1				3
+
+/* GPU_CC Resets */
+#define GPUCC_GPU_CC_CX_BCR			0
+#define GPUCC_GPU_CC_GMU_BCR			1
+#define GPUCC_GPU_CC_XO_BCR			2
+
+/* GPU_CC GDSCRs */
+#define GPU_CX_GDSC				0
+#define GPU_GX_GDSC				1
+
+#endif