ARM: dts: am57xx: cl-som-am57x: update SPI Flash frequency

On-board SPI flash cat act at 48Mhz SPI bus frequency.
Update the DT frequency property.
Signed-off-by: NDmitry Lifshitz <lifshitz@compulab.co.il>
Signed-off-by: NTony Lindgren <tony@atomide.com>

arch/arm/boot/dts/am57xx-cl-som-am57x.dts

@@ -492,14 +492,14 @@
 	pinctrl-names = "default";
 	pinctrl-0 = <&qspi1_pins>;
 
-	spi-max-frequency = <20000000>;
+	spi-max-frequency = <48000000>;
 
 	spi_flash: spi_flash@0 {
 		#address-cells = <1>;
 		#size-cells = <1>;
 		compatible = "spansion,m25p80", "jedec,spi-nor";
 		reg = <0>;				/* CS0 */
-		spi-max-frequency = <20000000>;
+		spi-max-frequency = <48000000>;
 
 		partition@0 {
 			label = "uboot";