Fix duplicate newlines at the end of files

Tools/serial/generate_config.py

@@ -330,4 +330,3 @@ if serial_params_output_file is not None:
         fid.write(template.render(serial_devices=serial_devices,
             ethernet_configuration=ethernet_configuration,
             commands=commands, serial_ports=serial_ports))
-

Tools/serial/rc.serial.jinja

@@ -30,4 +30,3 @@ unset PRT
 unset PRT_F
 unset BAUD_PARAM
 unset MAV_ARGS
-

Tools/serial/serial_params.c.jinja

@@ -70,4 +70,3 @@ PARAM_DEFINE_INT32({{ command.port_param_name }}, {{ command.default_port }});
 
 {% endfor -%}
 {% endif %}
-