imx6ul/imx6ull: synchronise device trees with linux

Synchronise device trees with linux v5.19-rc5.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
diff --git a/arch/arm/dts/imx6ul-pico-pi.dts b/arch/arm/dts/imx6ul-pico-pi.dts
index de07357..6cd7d58 100644
--- a/arch/arm/dts/imx6ul-pico-pi.dts
+++ b/arch/arm/dts/imx6ul-pico-pi.dts
@@ -43,7 +43,7 @@
 };
 
 &i2c2 {
-	clock_frequency = <100000>;
+	clock-frequency = <100000>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2c2>;
 	status = "okay";
@@ -58,7 +58,7 @@
 };
 
 &i2c3 {
-	clock_frequency = <100000>;
+	clock-frequency = <100000>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2c3>;
 	status = "okay";