ARM: dts: at91: sama5d27_wlsom1: update wilc rtc binding

Update wilc rtc binding to match the driver code & upstream patches.

Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>

Author: cristibirsan

arch/arm/boot/dts/at91-sama5d27_wlsom1.dtsi

@@ -367,7 +367,7 @@
 		pinctrl-0 = <&pinctrl_wilc_default>;
 		irq-gpios = <&pioA PIN_PB25 GPIO_ACTIVE_LOW>;
 		clocks = <&pmc PMC_TYPE_SYSTEM 9>;
-		clock-names = "rtc_clk";
+		clock-names = "rtc";
 		assigned-clocks = <&pmc PMC_TYPE_SYSTEM 9>;
 		assigned-clock-rates = <32768>;
 		status = "okay";