arm64: dts: st: enable RTC on stm32mp257f-ev1 board

Enable RTC on stm32mp257f-ev1 board.

Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

Author: VCASTM

arch/arm64/boot/dts/st/stm32mp257f-ev1.dts

@@ -93,6 +93,10 @@
 	status = "disabled";
 };
 
+&rtc {
+	status = "okay";
+};
+
 &scmi_regu {
 	scmi_vddio1: regulator@0 {
 		regulator-min-microvolt = <1800000>;