board: pttu: add dummy LED defines

boards/pttu/include/board.h

@@ -59,6 +59,18 @@ void bl_init_clks(void);
 #define STDIO_RX_BUFSIZE    (64U)
 /** @} */
 
+/**
+ * @name dummy-defines for LEDs
+ * @{
+ */
+#define LED_GREEN_ON        /* not available */
+#define LED_GREEN_OFF       /* not available */
+#define LED_GREEN_TOGGLE    /* not available */
+#define LED_RED_ON          /* not available */
+#define LED_RED_OFF         /* not available */
+#define LED_RED_TOGGLE      /* not available */
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif