staging: comedi: pcl726: remove the *_SIZE defines

The *_SIZE defines are only used to initialize the 'io_range' members in
the boardinfo. Remove the defines and just open code the values.

For aesthetics, change the type of the 'io_range' and rename it to better
match the 'len' parameter to comedi_request_region().

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>