dt-bindings: arm: renesas: Document Renesas RZ/V2H(P) System Controller

Add DT binding documentation for System Controller (SYS) found on
RZ/V2H(P) ("R9A09G057") SoC's.

SYS block contains the SYS_LSI_DEVID register which can be used to
retrieve SoC version information.

Signed-off-by: Lad Prabhakar <[e-mail]>
Reviewed-by: Fabrizio Castro <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Geert Uytterhoeven <[e-mail]>

Documentation/devicetree/bindings/soc/renesas/renesas,r9a09g057-sys.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/renesas/renesas,r9a09g057-sys.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/V2H(P) System Controller (SYS)
+
+maintainers:
+  - Geert Uytterhoeven <[e-mail]>
+
+description: |
+  The RZ/V2H(P) SYS (System Controller) controls the overall
+  configuration of the LSI and supports the following functions,
+  - Trust zone control
+  - Extend access by specific masters to address beyond 4GB space
+  - GBETH configuration
+  - Control of settings and states of SRAM/PCIe/CM33/CA55/CR8/xSPI/ADC/TSU
+  - LSI version
+  - WDT stop control
+  - General registers
+
+properties:
+  compatible:
+    const: renesas,r9a09g057-sys
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - resets
+
+additionalProperties: false
+
+examples:
+  - |
+    sys: system-controller@10430000 {
+        compatible = "renesas,r9a09g057-sys";
+        reg = <0x10430000 0x10000>;
+        clocks = <&cpg 1>;
+        resets = <&cpg 1>;
+    };