ps2_usb: Fix for V-USB build

converter/ps2_usb/Makefile.vusb

@@ -18,13 +18,13 @@ else
     SRC := keymap_plain.c $(SRC)
 endif
 
-# Use USART for PS/2. With V-USB INT and BUSYWAIT code is not useful.
-SRC += protocol/ps2_usart.c
-OPT_DEFS += -DPS2_USE_USART
-
 CONFIG_H = config.h
 
 
+# Use USART for PS/2. With V-USB INT and BUSYWAIT code is not useful.
+PS2_USE_USART = yes
+
+
 # V-USB debug level: To use ps2_usart.c level must be 0
 # ps2_usart.c requires USART to receive PS/2 signal.
 OPT_DEFS += -DDEBUG_LEVEL=0