staging: comedi: hwdrv_apci1564: use addi_tcw.h defines

Use the ADDI_TCW_CTRL_REG bit defines in addi_tcw.h to remove the "magic"
numbers.

Add some missing bit defines and mask defines to addi_tcw.h to help
cleanup the code.

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>