staging: comedi: pcmuio: tidy up the boardinfo

Remove the boilerplate comment about the boardinfo struct.

For aesthetic reasons, move the boardinfo declaration near the
struct definition.

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>