staging: comedi: rename addi CamelCase function pointers

Rename the CamelCase variable names for the ADDI subdevice
functions. This makes the code a bit cleaner and easier to
follow.

This will also help with converting the struct addi_board
boardtypes array to C99 style initialization to help with
maintaining the code.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: Mori Hess <fmhess@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>