HID: do not use down_interruptible() when unbinding devices

Action of unbinding driver from a device is not cancellable and should not
fail, and driver core does not pay attention to the result of "remove"
method, therefore using down_interruptible() in hid_device_remove() does
not make sense.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>