mwan3: fix reload handling

When the interface section was changed, the changed configuration
options were not applied.
This commit adds the service reload handling again.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>

net/mwan3/files/etc/init.d/mwan3

@@ -111,6 +111,11 @@ stop_service() {
 	mwan3_unlock "command" "mwan3"
 }
 
+reload_service() {
+	stop
+	start
+}
+
 service_triggers() {
 	procd_add_reload_trigger 'mwan3'
 }