media: dt-bindings: st,stm32-cec: move to cec subfolder

Move st,stm32-cec.yaml bindings to cec subfolder and drop unneeded
"bindings" in the title.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

Documentation/devicetree/bindings/media/cec/st,stm32-cec.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/media/cec/st,stm32-cec.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STM32 CEC
+
+maintainers:
+  - Yannick Fertre <yannick.fertre@foss.st.com>
+
+properties:
+  compatible:
+    const: st,stm32-cec
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: Module Clock
+      - description: Bus Clock
+
+  clock-names:
+    items:
+      - const: cec
+      - const: hdmi-cec
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/stm32mp1-clks.h>
+    cec: cec@40006c00 {
+        compatible = "st,stm32-cec";
+        reg = <0x40006c00 0x400>;
+        interrupts = <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&rcc CEC_K>, <&clk_lse>;
+        clock-names = "cec", "hdmi-cec";
+    };
+
+...