license: add missing License-Identifier

Somehow we missed this when the files were created.

Author: dlech

bricks/ev3dev/pb_type_ev3dev_font.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier
+// SPDX-License-Identifier: MIT
 // Copyright (c) 2013, 2014 Damien P. George
 // Copyright (c) 2019-2020 The Pybricks Authors
 

bricks/ev3dev/pb_type_ev3dev_image.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier
+// SPDX-License-Identifier: MIT
 // Copyright (c) 2013, 2014 Damien P. George
 // Copyright (c) 2019-2020 The Pybricks Authors
 

bricks/ev3dev/pb_type_ev3dev_speaker.c

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier
+// SPDX-License-Identifier: MIT
 // Copyright (c) 2018-2020 The Pybricks Authors
 
 // class Speaker

lib/lego/lego_uart.h

@@ -1,4 +1,4 @@
-// SPDX-License-Identifier
+// SPDX-License-Identifier: MIT
 // Copyright (c) 2019-2020 The Pybricks Authors
 
 // LEGO UART Message Protocol (LUMP) for EV3 and Powered Up I/O devices
@@ -475,7 +475,7 @@ typedef enum {
     LUMP_TYPE_ID_TECHNIC_M_ANGULAR_MOTOR  = 75,
 
     /** Technic Large Angular Motor */
-    LUMP_TYPE_ID_TECHNIC_L_ANGULAR_MOTOR  = 76,    
+    LUMP_TYPE_ID_TECHNIC_L_ANGULAR_MOTOR  = 76,
 
 } lump_type_id_t;