scd: Fix for USB INTERRUPT transfer.

* scd/ccid-driver.c (intr_cb): When LIBUSB_TRANSFER_NO_DEVICE,
just handle this event as failure.

It used to try another interrupt transfer request to make sure
if it fails again.

• GnuPG-bug-id: T4308
• Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>