lenovo tpkbd currently relies on the usb interface number to detect
if it is dealing with the touchpad interface or not.
As the report descriptors of the interface 0 does not contain the
button 3, we can use this to remove the need to check for usb.
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>