tools: Mass fixing of empty prototypes (for -Wstrict-prototypes)

examples/peripherals/uart/uart_echo/main/uart_echo_example_main.c

@@ -31,7 +31,7 @@
 
 #define BUF_SIZE (1024)
 
-static void echo_task()
+static void echo_task(void)
 {
     /* Configure parameters of an UART driver,
      * communication pins and install the driver */
@@ -57,7 +57,7 @@ static void echo_task()
     }
 }
 
-void app_main()
+void app_main(void)
 {
     xTaskCreate(echo_task, "uart_echo_task", 1024, NULL, 10, NULL);
 }