dts: stm32u5: Add jtag debug port node

Provide jtag port pins description, so they can be used to be set in
analog mode when not required to save power (around 40uA saved in total).

Signed-off-by: Erwan Gouriou <erwan.gouriou@st.com>

dts/arm/st/u5/stm32u5.dtsi

@@ -140,6 +140,12 @@
 		};
 	};
 
+	jtag_port: jtag_port {
+		compatible = "gpio-jtag";
+		jtag-gpios = <&gpioa 13 0>, <&gpioa 14 0>, <&gpioa 15 0>,
+			     <&gpiob 3 0> ,<&gpiob 4 0>;
+		};
+
 	soc {
 		flash: flash-controller@40022000 {
 			compatible = "st,stm32-flash-controller", "st,stm32l5-flash-controller";