staging: comedi: das16m1: tidy up register map comment

The comment about all the registers is not neccessary. The defines
give the same information. This also fixes a checkpatch.pl issue:
WARNING: Block comments use * on subsequent lines

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>