staging: comedi: rtd520: remove RtdAdcSampleCounterSource 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 sample counter source select (write only) */
-#define RtdAdcSampleCounterSource(dev, v) \
-	writel(v, devpriv->las0+LAS0_ADC_SCNT_SRC)
-
 /* Set Pacer trigger mode select (write only) 0=single cycle, 1=repeat */
 #define RtdPacerTriggerMode(dev, v) \
 	writel((v > 0) ? 1 : 0, devpriv->las0+LAS0_PACER_REPEAT)