USB: input: appletouch: fix up compiler warning

My last patch fixing up the dev_* messages caused a compiler warning
accidentally for an unused variable.  Fix this up, as it was my fault.

Cc: Alessandro Rubini <rubini@ipvvis.unipv.it>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/input/mouse/appletouch.c

@@ -402,7 +402,6 @@ static inline void atp_report_fingers(struct input_dev *input, int fingers)
 static int atp_status_check(struct urb *urb)
 {
 	struct atp *dev = urb->context;
-	struct input_dev *idev = dev->input;
 	struct usb_interface *intf = dev->intf;
 
 	switch (urb->status) {