staging: comedi: das08: rename DAS08_TRIG_12BIT
staging: comedi: das08: rename DAS08_TRIG_12BIT

The `DAS08_TRIG_12BIT` macro contains the offset to the write-only
software trigger register for 12-bit or 16-bit analog-to-digital
conversions.  Rename the macro to `DAS08_AI_TRIG_REG` and add a comment.

Signed-off-by: Ian Abbott <9e6ba6483b6a3e14d61f7c987e72ecb5b46122d6@mev.co.uk>
Reviewed-by: H Hartley Sweeten <382ff55d8e07d1082d179e669636cd1552da4f36@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs