staging: comedi: adq12b: remove ADQ12B_SIZE define

This define is only used in the comedi_request_region() call to
specify the I/O resource size. Remove it and just open code the
value.

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>