usb: misc: adutux: use swap()

Use swap() in order to make code cleaner. Issue found by coccinelle.

Signed-off-by: Salah Triki <salah.triki@gmail.com>
Link: https://lore.kernel.org/r/20210803005343.GA1578854@pc


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>