lufa: usb-usb: Use LUFA startup instead of cusotom

- Change keyboard_init() timing and matrix_scan() is called in USB
  startup wait loop for FC660C
- FC660C startup seems to be faster and it doesn't work without this fix
  when plugin the keyboard and converter at same time

tmk_core/protocol/lufa/lufa.c

@@ -643,6 +643,8 @@ int main(void)
 
     sei();
 
+    keyboard_init();
+
     /* wait for USB startup */
     while (USB_DeviceState != DEVICE_STATE_Configured) {
 #if defined(INTERRUPT_CONTROL_ENDPOINT)
@@ -650,10 +652,9 @@ int main(void)
 #else
         USB_USBTask();
 #endif
+        matrix_scan();
     }
 
-    keyboard_init();
-
     hook_late_init();
 
     print("\nKeyboard start.\n");