ARM: dts: exynos: enable PMIC wakeup from suspend on Origen4412

The RTC on S5M8767 PMIC can wakeup the system from suspend to RAM.
Add a generic property for this.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20210420164943.11152-2-krzysztof.kozlowski@canonical.com

arch/arm/boot/dts/exynos4412-origen.dts

@@ -144,6 +144,7 @@ pmic@66 {
 						 <1200000>, <1200000>,
 						 <1200000>, <1200000>,
 						 <1200000>, <1200000>;
+		wakeup-source;
 
 		s5m8767_osc: clocks {
 			compatible = "samsung,s5m8767-clk";