ARM: dts: stm32: add DSI support on stm32f769

Add support for MIPI DSI Host controller. Since MIPI DSI is not
available on stm32f746, the patch adds the "stm32f769.dtsi" file
containing the dsi node inside.
Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/st/stm32f769.dtsi

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2023 Dario Binacchi <dario.binacchi@amarulasolutions.com>
+ */
+
+#include "stm32f746.dtsi"
+
+/ {
+	soc {
+		dsi: dsi@40016c00 {
+			compatible = "st,stm32-dsi";
+			reg = <0x40016c00 0x800>;
+			clocks = <&rcc 1 CLK_F769_DSI>, <&clk_hse>;
+			clock-names = "pclk", "ref";
+			resets = <&rcc STM32F7_APB2_RESET(DSI)>;
+			reset-names = "apb";
+			status = "disabled";
+		};
+	};
+};