arm64: dts: allwinner: a64: add device tree node for HDMI simplefb

As the U-Boot bootloader now is also capable of initialize the HDMI on
A64 boards, add a simplefb device tree node for accessing the HDMI
framebuffer initialized by the bootloader.
Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi

@@ -68,6 +68,15 @@ simplefb_lcd: framebuffer-lcd {
 				 <&display_clocks CLK_MIXER0>;
 			status = "disabled";
 		};
+
+		simplefb_hdmi: framebuffer-hdmi {
+			compatible = "allwinner,simple-framebuffer",
+				     "simple-framebuffer";
+			allwinner,pipeline = "mixer1-lcd1-hdmi";
+			clocks = <&display_clocks CLK_MIXER1>,
+				 <&ccu CLK_TCON1>, <&ccu CLK_HDMI>;
+			status = "disabled";
+		};
 	};
 
 	cpus {