ARM: dts: stm32: add CEC for stm32f7 family

add cec in devicetree for stm32f7 family
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32f746.dtsi

@@ -167,6 +167,15 @@ usart5: serial@40005000 {
 			status = "disabled";
 		};
 
+		cec: cec@40006c00 {
+			compatible = "st,stm32-cec";
+			reg = <0x40006C00 0x400>;
+			interrupts = <94>;
+			clocks = <&rcc 0 STM32F7_APB1_CLOCK(CEC)>, <&rcc 1 CLK_HDMI_CEC>;
+			clock-names = "cec", "hdmi-cec";
+			status = "disabled";
+		};
+
 		usart7: serial@40007800 {
 			compatible = "st,stm32f7-usart", "st,stm32f7-uart";
 			reg = <0x40007800 0x400>;
@@ -336,6 +345,15 @@ gpiok: gpio@40022800 {
 				st,bank-name = "GPIOK";
 			};
 
+			cec_pins_a: cec@0 {
+				pins {
+					pinmux = <STM32F746_PA15_FUNC_HDMI_CEC>;
+					slew-rate = <0>;
+					drive-open-drain;
+					bias-disable;
+				};
+			};
+
 			usart1_pins_a: usart1@0 {
 				pins1 {
 					pinmux = <STM32F746_PA9_FUNC_USART1_TX>;