soc: arm: stm32g0 add rtc feature on this serie

This patch enables the rtc clock on the stm32g0 soc
from STMicroelectronics.

Signed-off-by: Francois Ramu <[email protected]>

Author: FRASTM

dts/arm/st/g0/stm32g0.dtsi

@@ -111,6 +111,16 @@
 			};
 		};
 
+		rtc: rtc@40002800 {
+			compatible = "st,stm32-rtc";
+			reg = <0x40002800 0x400>;
+			interrupts = <2 0>;
+			clocks = <&rcc STM32_CLOCK_BUS_APB1 0x00000400>;
+			prescaler = <32768>;
+			status = "disabled";
+			label = "RTC_0";
+		};
+
 		iwdg: watchdog@40003000 {
 			compatible = "st,stm32-watchdog";
 			reg = <0x40003000 0x400>;