Remove USBCON from the compile flags

Author: GrumpyOldPizza

platform.txt

@@ -66,7 +66,7 @@ compiler.elf2hex.extra_flags=
 
 # USB Flags
 # ---------
-build.usb_flags=-DUSB_VID={build.vid} -DUSB_PID={build.pid} -DUSBCON '-DUSB_MANUFACTURER={build.usb_manufacturer}' '-DUSB_PRODUCT={build.usb_product}' '-DUSB_TYPE={build.usb_type}'
+build.usb_flags=-DUSB_VID={build.vid} -DUSB_PID={build.pid} '-DUSB_MANUFACTURER={build.usb_manufacturer}' '-DUSB_PRODUCT={build.usb_product}' '-DUSB_TYPE={build.usb_type}'
 
 # Compile patterns
 # ----------------