staging: comedi: rtd520: remove RtdTriggerPolarity macro

This macro uses the 'devpriv' macro which relies on a local variable
having a specific name. It's also not used. Remove it.
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 */
 
-/* Set external trigger polarity (write only) 0=positive edge, 1=negative */
-#define RtdTriggerPolarity(dev, v) \
-	writel((v > 0) ? 1 : 0, devpriv->las0+LAS0_ETRG_POLARITY)
-
 /* Start single ADC conversion */
 #define RtdAdcStart(dev) \
 	writew(0, devpriv->las0+LAS0_ADC)