staging: comedi: dmm32at: remove forward declarations 1

Move the attach/detach functions as well as the boardinfo variable
to remove the need to most of the forward declarations.

Add some whitespace to the boardinfo during the move.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>