ARM: dts: exynos: enable PMIC wakeup from suspend on Itop Core

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/20210420164943.11152-1-krzysztof.kozlowski@canonical.com

arch/arm/boot/dts/exynos4412-itop-scp-core.dtsi

@@ -163,6 +163,7 @@ s5m8767: pmic@66 {
 						 <1025000>, <950000>,
 						 <918750>, <900000>,
 						 <875000>, <831250>;
+		wakeup-source;
 
 		regulators {
 			ldo1_reg: LDO1 {