boards: enable the WCH EXTI peripheral on all WCH boards

Now that Zephyr has support, enable by default.

Signed-off-by: Michael Hope <michaelh@juju.nz>

boards/wch/ch32v003evt/ch32v003evt.dts

@@ -68,6 +68,10 @@
 	clocks = <&pll>;
 };
 
+&exti {
+	status = "okay";
+};
+
 &gpioc {
 	status = "okay";
 };

boards/wch/ch32v006evt/ch32v006evt.dts

@@ -75,6 +75,10 @@
 	clocks = <&pll>;
 };
 
+&exti {
+	status = "okay";
+};
+
 &gpioc {
 	status = "okay";
 };

boards/wch/linkw/linkw.dts

@@ -69,6 +69,10 @@
 	clocks = <&pll>;
 };
 
+&exti {
+	status = "okay";
+};
+
 &gpioa {
 	status = "okay";
 };