staging: comedi: adl_pci9118: rename boardinfo struct

For aesthetics, rename the struct used for the boardinfo so it has
namespace associated with the driver. Also, rename the local variable
used for the boardinfo pointer to simply 'board'.

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>