staging: comedi: comedidev.h: tweak struct comedi_async documentation

Make the kernel-doc layout for `struct comedi_async` more consistent
with the documentation for the other COMEDI data types.

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