ARM: dts: imx6ull-dhcor: Remove 900MHz operating point

Due to CPU lifetime consideration of the SoC manufacturer [1] and
the preferred area of operation in the industrial related
environment, set the maximum frequency for each DHCOM i.MX6ULL to
792MHz, as with the industrial type. This is done by removing the
operating point at 900MHz and set the clock-frequency to 792000000.

[1] https://www.nxp.com/docs/en/application-note/AN5337.pdfSigned-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/nxp/imx/imx6ull-dhcor-som.dtsi

@@ -28,10 +28,14 @@ &cpu0 {
 	/*
 	 * Due to the design as a solderable SOM, there are no capacitors
 	 * below the SoC, therefore higher voltages are required.
+	 * Due to CPU lifetime consideration of the SoC manufacturer and
+	 * the preferred area of operation in the industrial related
+	 * environment, set the maximum frequency for each DHCOM i.MX6ULL
+	 * to 792MHz, as with the industrial type.
 	 */
+	clock-frequency = <792000000>;
 	operating-points = <
 		/* kHz	uV */
-		900000	1275000
 		792000	1250000 /* Voltage increased */
 		528000	1175000
 		396000	1025000
@@ -39,7 +43,6 @@ &cpu0 {
 	>;
 	fsl,soc-operating-points = <
 		/* KHz	uV */
-		900000	1250000
 		792000	1250000 /* Voltage increased */
 		528000	1175000
 		396000	1175000