Only check if the abort transfer is the interrupt one if the pipe is

Only check if the abort transfer is the interrupt one if the pipe is
opened with a callback.

If a driver opens an interrupt pipe without callback function, like
umct(4) does with one of its bulk in endpoints being reported as an
interrupt endpoint, then we can end up aborting a transfer which is
different from the interrupt one.

Issue reported by Roberto E. Vargas Caballero, ok deraadt@