arm64: dts: meson-gx: Add hdmi_5v regulator as hdmi tx supply

The hdmi_5v regulator must be enabled to provide power to the physical HDMI
PHY and enables the HDMI 5V presence loopback for the monitor.

Fixes: b409f625a6d5 ("ARM64: dts: meson-gx: Add HDMI_5V regulator on selected boards")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
[backport of linux commit e1f2163deac059ad39f07aba9e314ebe605d5a7a]
diff --git a/arch/arm/dts/meson-gxm-khadas-vim2.dts b/arch/arm/dts/meson-gxm-khadas-vim2.dts
index 313f88f..782e9ed 100644
--- a/arch/arm/dts/meson-gxm-khadas-vim2.dts
+++ b/arch/arm/dts/meson-gxm-khadas-vim2.dts
@@ -271,6 +271,7 @@
 	status = "okay";
 	pinctrl-0 = <&hdmi_hpd_pins>, <&hdmi_i2c_pins>;
 	pinctrl-names = "default";
+	hdmi-supply = <&hdmi_5v>;
 };
 
 &hdmi_tx_tmds_port {