staging: comedi: rti802: remove RTI802_SIZE define

This define is only used in the attach to specify the I/O region size
passed to comedi_request_region(). Remove the define 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>