arm64: dts: imx8mp: Align both CSI2 pixel clock

Configure both CSI2 clock-frequency and assigned-clock-rates
the same way. There does not seem to be any reason for keeping
the two CSI2 pixel clock set to different frequencies.

This also reduces first CSI2 clock from overdrive mode
frequency which is 500 MHz down below the regular mode
frequency of 400 MHz.
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mp.dtsi

@@ -1657,7 +1657,7 @@ mipi_csi_0: csi@32e40000 {
 				compatible = "fsl,imx8mp-mipi-csi2", "fsl,imx8mm-mipi-csi2";
 				reg = <0x32e40000 0x10000>;
 				interrupts = <GIC_SPI 17 IRQ_TYPE_LEVEL_HIGH>;
-				clock-frequency = <500000000>;
+				clock-frequency = <266000000>;
 				clocks = <&clk IMX8MP_CLK_MEDIA_APB_ROOT>,
 					 <&clk IMX8MP_CLK_MEDIA_CAM1_PIX_ROOT>,
 					 <&clk IMX8MP_CLK_MEDIA_MIPI_PHY1_REF_ROOT>,
@@ -1667,7 +1667,7 @@ mipi_csi_0: csi@32e40000 {
 						  <&clk IMX8MP_CLK_MEDIA_MIPI_PHY1_REF>;
 				assigned-clock-parents = <&clk IMX8MP_SYS_PLL2_1000M>,
 							 <&clk IMX8MP_CLK_24M>;
-				assigned-clock-rates = <500000000>;
+				assigned-clock-rates = <266000000>;
 				power-domains = <&media_blk_ctrl IMX8MP_MEDIABLK_PD_MIPI_CSI2_1>;
 				status = "disabled";