dt-bindings: timer: Add NXP System Timer Module

Add the System Timer Module description found on the NXP s32 platform
and the compatible for the s32g2 variant.

Cc: Ghennadi Procopciuc <[e-mail]>
Cc: Thomas Fossati <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Reviewed-by: Rob Herring (Arm) <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Daniel Lezcano <[e-mail]>

Documentation/devicetree/bindings/timer/nxp,s32g2-stm.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/nxp,s32g2-stm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP System Timer Module (STM)
+
+maintainers:
+  - Daniel Lezcano <[e-mail]>
+
+description:
+  The System Timer Module supports commonly required system and application
+  software timing functions. STM includes a 32-bit count-up timer and four
+  32-bit compare channels with a separate interrupt source for each channel.
+  The timer is driven by the STM module clock divided by an 8-bit prescale
+  value.
+
+properties:
+  compatible:
+    oneOf:
+      - const: nxp,s32g2-stm
+      - items:
+          - const: nxp,s32g3-stm
+          - const: nxp,s32g2-stm
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Counter clock
+      - description: Module clock
+      - description: Register clock
+
+  clock-names:
+    items:
+      - const: counter
+      - const: module
+      - const: register
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    timer@4011c000 {
+        compatible = "nxp,s32g2-stm";
+        reg = <0x4011c000 0x3000>;
+        interrupts = <GIC_SPI 24 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&clks 0x3b>, <&clks 0x3c>, <&clks 0x3c>;
+        clock-names = "counter", "module", "register";
+    };