usb: Add missing unsetup while detaching uchcom

Reviewed by:    christos
MFC after:      2 weeks
Sponsored by:   The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D57329

sys/dev/usb/serial/uchcom.c

@@ -404,6 +404,7 @@ uchcom_detach(device_t dev)
 	DPRINTFN(11, "\n");
 
 	ucom_detach(&sc->sc_super_ucom, &sc->sc_ucom);
+	usbd_transfer_unsetup(&sc->sc_intr_xfer, 1);
 	usbd_transfer_unsetup(sc->sc_xfer, UCHCOM_N_TRANSFER);
 
 	device_claim_softc(dev);