dts: bindings: pwm: add sifli,sf32lb-gpt-pwm

Add gpt based pwm device bindings for sf32lb platform

Signed-off-by: Qingsong Gou <[email protected]>

Author: ck-telecom

dts/bindings/pwm/sifli,sf32lb-gpt-pwm.yaml

@@ -0,0 +1,23 @@
+# Copyright (c) 2025, Qingsong Gou <[email protected]>
+# SPDX-License-Identifier: Apache-2.0
+
+description: Sifli PWM controller
+
+compatible: "sifli,sf32lb-gpt-pwm"
+
+include: [base.yaml, pwm-controller.yaml, pinctrl-device.yaml]
+
+properties:
+  pinctrl-0:
+    required: true
+
+  pinctrl-names:
+    required: true
+
+  "#pwm-cells":
+    const: 3
+
+pwm-cells:
+  - channel
+  - period
+  - flags