The interrupt URB is killed at final port close since commit 0de9a7024e7a ("USB: overhaul of mos7840 driver").
Fixes: 0de9a7024e7a ("USB: overhaul of mos7840 driver") Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk>