ARM: dts: genmai: Enable rtc and rtc_x1 clock

Enable the 32.768 kHz RTC_X1 clock by setting the frequency value to
non-zero and enable the realtime clock.
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/boot/dts/r7s72100-genmai.dts

@@ -44,6 +44,10 @@ &usb_x1_clk {
 	clock-frequency = <48000000>;
 };
 
+&rtc_x1_clk {
+	clock-frequency = <32768>;
+};
+
 &mtu2 {
 	status = "okay";
 };
@@ -59,6 +63,10 @@ eeprom@50 {
 	};
 };
 
+&rtc {
+	status = "okay";
+};
+
 &scif2 {
 	status = "okay";
 };