ARM: dts: imx7d-pico: Use 'clock-frequency'

'clock_frequency' is not a valid property.

Use the correct 'clock-frequency' instead.

Fixes: 8b646cfb ("ARM: dts: imx7d-pico: Add support for the dwarf baseboard")
Fixes: 6418fd92 ("ARM: dts: imx7d-pico: Add support for the nymph baseboard")
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx7d-pico-dwarf.dts

@@ -32,7 +32,7 @@ sys_mclk: clock-sys-mclk {
 };
 
 &i2c1 {
-	clock_frequency = <100000>;
+	clock-frequency = <100000>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2c1>;
 	status = "okay";
@@ -52,7 +52,7 @@ pressure-sensor@60 {
 };
 
 &i2c4 {
-	clock_frequency = <100000>;
+	clock-frequency = <100000>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2c1>;
 	status = "okay";

arch/arm/boot/dts/imx7d-pico-nymph.dts

@@ -43,7 +43,7 @@ sys_mclk: clock-sys-mclk {
 };
 
 &i2c1 {
-	clock_frequency = <100000>;
+	clock-frequency = <100000>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2c1>;
 	status = "okay";
@@ -64,7 +64,7 @@ adc@52 {
 };
 
 &i2c2 {
-	clock_frequency = <100000>;
+	clock-frequency = <100000>;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2c2>;
 	status = "okay";