imx: kontron-sl-mx8mm: Prepare for I2C display detection in environment script

Enable the I2C bus and set a env variable for the reset GPIO of the touch
controller. This allows us to probe the panel in a script.

Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Reviewed-by: Fabio Estevam <festevam@denx.de>
diff --git a/arch/arm/dts/imx8mm-kontron-bl-common-u-boot.dtsi b/arch/arm/dts/imx8mm-kontron-bl-common-u-boot.dtsi
index e7e900d..5b8b472 100644
--- a/arch/arm/dts/imx8mm-kontron-bl-common-u-boot.dtsi
+++ b/arch/arm/dts/imx8mm-kontron-bl-common-u-boot.dtsi
@@ -48,8 +48,17 @@
 
 &i2c2 {
 	status = "okay";
-	u-boot,dm-spl;
-	u-boot,dm-pre-reloc;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_i2c2>;
+};
+
+&iomuxc {
+	pinctrl_i2c2: i2c2grp {
+		fsl,pins = <
+			MX8MM_IOMUXC_I2C2_SCL_I2C2_SCL		0x400001c3
+			MX8MM_IOMUXC_I2C2_SDA_I2C2_SDA		0x400001c3
+		>;
+	};
 };
 
 &pinctrl_ecspi1 {