arm64: dts: colibri-imx8x: Add pinctrl group for hdmi hpd

The colibri imx8x contains a dedicated gpio meant for HDMI
hot-plug-detect. Add a pinctrl group to make this usable.
Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8x-colibri.dtsi

@@ -218,6 +218,11 @@ pinctrl_gpio_bl_on: gpioblongrp {
 		fsl,pins = <IMX8QXP_QSPI0A_DATA3_LSIO_GPIO3_IO12		0x60>;		/* SODIMM  71 */
 	};
 
+	/* HDMI Hot Plug Detect on FFC (X2) */
+	pinctrl_gpio_hpd: gpiohpdgrp {
+		fsl,pins = <IMX8QXP_MIPI_DSI1_GPIO0_00_LSIO_GPIO1_IO31		0x20>;		/* SODIMM 138 */
+	};
+
 	pinctrl_gpiokeys: gpiokeysgrp {
 		fsl,pins = <IMX8QXP_QSPI0A_DATA1_LSIO_GPIO3_IO10		0x06700041>;	/* SODIMM  45 */
 	};