staging: comedi: rtd520: remove RtdDio0CtrlRead 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

@@ -406,8 +406,6 @@ struct rtdPrivate {
 
 /* Macros to access registers */
 
-#define RtdDio0CtrlRead(dev) \
-	(readw(devpriv->las0+LAS0_DIO0_CTRL) & 0xff)
 #define RtdDio0CtrlWrite(dev, v) \
 	writew((v) & 0xff, devpriv->las0+LAS0_DIO0_CTRL)