media: dt-bindings: st,stm32-cec: drop obsolete file

The st,stm32-cec.yaml was moved to media/cec directory, however the
"remove" part disappeared during applying.

Link: https://lore.kernel.org/all/20221208103115.25512-3-krzysztof.kozlowski@linaro.org/

Fixes: 8f437662 ("media: dt-bindings: st,stm32-cec: move to cec subfolder")
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

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

-# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
-%YAML 1.2
----
-$id: http://devicetree.org/schemas/media/st,stm32-cec.yaml#
-$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";
-    };
-
-...