staging: comedi: daqboard2000: rename trigger control register macros

Rename the macros that define values for the trigger control register to
avoid CamelCase, and to make it clearer which register they are
associated with.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>