Removed 'USB_MANUFACTURER' constant redefinition for known VIDs.

See arduino#1877

Author: cmaglie

cores/arduino/USB/USBCore.cpp

@@ -69,10 +69,13 @@ const uint16_t STRING_LANGUAGE[2] = {
 const uint8_t STRING_PRODUCT[] = USB_PRODUCT;
 
 #if USB_VID == 0x2341
-#define USB_MANUFACTURER "Arduino LLC"
+#  if defined(USB_MANUFACTURER)
+#    undef USB_MANUFACTURER
+#  endif
+#  define USB_MANUFACTURER "Arduino LLC"
 #elif !defined(USB_MANUFACTURER)
 // Fall through to unknown if no manufacturer name was provided in a macro
-#define USB_MANUFACTURER "Unknown"
+#  define USB_MANUFACTURER "Unknown"
 #endif
 
 const uint8_t STRING_MANUFACTURER[12] = USB_MANUFACTURER;