staging: comedi: amplc_dio200_common: document spinlock definition

Fix the checkpatch.pl issue:
CHECK: spinlock_t definition without comment

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 file changed