Input: drivers/usb/input - usb_buffer_free() cleanup

usb_buffer_free() now handles NULLs so remove unneeded checks
form callers.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/usb/input/usbtouchscreen.c b/drivers/usb/input/usbtouchscreen.c
index e082941..8e18e6c 100644
--- a/drivers/usb/input/usbtouchscreen.c
+++ b/drivers/usb/input/usbtouchscreen.c
@@ -668,9 +668,8 @@
 static void usbtouch_free_buffers(struct usb_device *udev,
 				  struct usbtouch_usb *usbtouch)
 {
-	if (usbtouch->data)
-		usb_buffer_free(udev, usbtouch->type->rept_size,
-		                usbtouch->data, usbtouch->data_dma);
+	usb_buffer_free(udev, usbtouch->type->rept_size,
+	                usbtouch->data, usbtouch->data_dma);
 	kfree(usbtouch->buffer);
 }