ARM: dts: stm32: Add LP timer wakeup-source on stm32mp151

LP timer can be used to wakeup from stop mode on stm32mp151.
Add wakeup-source properties to all LP timer instances.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp151.dtsi

@@ -365,6 +365,7 @@ lptimer1: timer@40009000 {
 			interrupts-extended = <&exti 47 IRQ_TYPE_LEVEL_HIGH>;
 			clocks = <&rcc LPTIM1_K>;
 			clock-names = "mux";
+			wakeup-source;
 			status = "disabled";
 
 			pwm {
@@ -1160,6 +1161,7 @@ lptimer2: timer@50021000 {
 			interrupts-extended = <&exti 48 IRQ_TYPE_LEVEL_HIGH>;
 			clocks = <&rcc LPTIM2_K>;
 			clock-names = "mux";
+			wakeup-source;
 			status = "disabled";
 
 			pwm {
@@ -1188,6 +1190,7 @@ lptimer3: timer@50022000 {
 			interrupts-extended = <&exti 50 IRQ_TYPE_LEVEL_HIGH>;
 			clocks = <&rcc LPTIM3_K>;
 			clock-names = "mux";
+			wakeup-source;
 			status = "disabled";
 
 			pwm {
@@ -1209,6 +1212,7 @@ lptimer4: timer@50023000 {
 			interrupts-extended = <&exti 52 IRQ_TYPE_LEVEL_HIGH>;
 			clocks = <&rcc LPTIM4_K>;
 			clock-names = "mux";
+			wakeup-source;
 			status = "disabled";
 
 			pwm {
@@ -1224,6 +1228,7 @@ lptimer5: timer@50024000 {
 			interrupts-extended = <&exti 53 IRQ_TYPE_LEVEL_HIGH>;
 			clocks = <&rcc LPTIM5_K>;
 			clock-names = "mux";
+			wakeup-source;
 			status = "disabled";
 
 			pwm {