Put Teensy supported board warning in nested if

Will only warn about supported Teensy boards if using an unsupported Teensy board, and not for other board types

Author: dmadison

src/XInput.cpp

@@ -30,17 +30,16 @@
 #warning "USB type is not set to XInput in boards menu! Board will not behave as an XInput device"
 #endif
 
-// Teensy 3.1-3.2:  __MK20DX256__
-// Teensy LC:       __MKL26Z64__
-// Teensy 3.5:      __MK64FX512__
-// Teensy 3.6:      __MK66FX1M0__
-
-#if defined(TEENSYDUINO) && \
-	(defined(__MK20DX256__) || defined(__MKL26Z64__) || \
-	 defined(__MK64FX512__) || defined(__MK66FX1M0__))
-#else
-#warning "Not a supported board! Must use Teensy 3.1/3.2, LC, 3.5, or 3.6"
-#endif
+#if defined(TEENSYDUINO)
+	// Teensy 3.1-3.2:  __MK20DX256__
+	// Teensy LC:       __MKL26Z64__
+	// Teensy 3.5:      __MK64FX512__
+	// Teensy 3.6:      __MK66FX1M0__
+#if  !defined(__MK20DX256__) && !defined(__MKL26Z64__) && \
+	 !defined(__MK64FX512__) && !defined(__MK66FX1M0__)
+	#warning "Not a supported board! Must use Teensy 3.1/3.2, LC, 3.5, or 3.6"
+#endif /* if supported Teensy board */
+#endif /* if defined(TEENSYDUINO) */
 
 // --------------------------------------------------------
 // XInput Button Maps                                     |