Staging: comedi: remove C99 comments in hwdrv_apci3120.c

This replaces C99 comments with traditional C comments.  This
also removes 3 blocks of code that were already commented out.

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>