staging: comedi: rtd520: remove RtdDacBothUpdate macro

This macro uses the 'devpriv' macro which relies on a local variable
having a specific name. It's also not used. Remove the macro.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/rtd520.c

@@ -406,10 +406,6 @@ struct rtdPrivate {
 
 /* Macros to access registers */
 
-/* Start single DAC conversion on both DACs */
-#define RtdDacBothUpdate(dev) \
-	writew(0, devpriv->las0+LAS0_DAC)
-
 /* Set DAC output type and range */
 #define RtdDacRange(dev, n, v) \
 	writew((v) & 7, devpriv->las0 \