at76_debug should be an unsigned int as it used as a bit field.  In
fact, modprobe fails when trying to set at76_debug's high bit.
Signed-off-by: NJason Andryuk <jandryuk@gmail.com>
Signed-off-by: NKalle Valo <kalle.valo@iki.fi>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>