USB: remove usb_find_device

Now on one uses this function and it seems useless,
so remove usb_find_device.

[tom@tom linux-2.6-next]$ grep -r -n -I usb_find_device ./
drivers/media/dvb/dvb-usb/dvb-usb-init.c:160:static struct
dvb_usb_device_description * dvb_usb_find_device(struct usb_device
*udev,struct dvb_usb_device_properties *props, int *cold)

drivers/media/dvb/dvb-usb/dvb-usb-init.c:230:   if ((desc =
dvb_usb_find_device(udev,props,&cold)) == NULL) {

drivers/usb/core/usb.c:630: * usb_find_device - find a specific usb device in the system
drivers/usb/core/usb.c:642:struct usb_device *usb_find_device(u16 vendor_id, u16 product_id)

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>