ARM: dts: rza2mevb: Add 48MHz USB clock

The RZ/A2M EVB has a 48MHz clock attached to USB_X1.
Signed-off-by: Chris Brandt <chris.brandt@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r7s9210-rza2mevb.dts

@@ -58,6 +58,11 @@ &rtc_x1_clk {
 	clock-frequency = <32768>;
 };
 
+/* USB_X1 */
+&usb_x1_clk {
+	clock-frequency = <48000000>;
+};
+
 &pinctrl {
 	/* Serial Console */
 	scif4_pins: serial4 {