USB: remove unused defintion of struct usb_device_status

The recent rework of /proc/bus/usb/devices polling support made
this structure unused so let's remove it.

Signed-off-by: Dmitry Torokhov <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/usb/core/devices.c

···
 	.wait = __WAIT_QUEUE_HEAD_INITIALIZER(device_event.wait)
 };
 
-/* this struct stores the poll state for <mountpoint>/devices pollers */
-struct usb_device_status {
-	unsigned int lastev;
-};
-
 struct class_info {
 	int class;
 	char *class_name;