staging: comedi: adq12b: remove 'unipolar' from private data

This member of the private data is only used during the attach to
determine which range table to use for the analog inputs. Remove
the member and use the comedi_devconfig option directly.
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>

drivers/staging/comedi/drivers/adq12b.c

@@ -114,7 +114,6 @@ static const struct comedi_lrange range_adq12b_ai_unipolar = {
 };
 
 struct adq12b_private {
-	int unipolar;		/* option 2 of comedi_config (1 is iobase) */
 	int differential;	/* option 3 of comedi_config */
 	unsigned int last_ctreg;
 };
@@ -218,7 +217,6 @@ static int adq12b_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	if (!devpriv)
 		return -ENOMEM;
 
-	devpriv->unipolar = it->options[1];
 	devpriv->differential = it->options[2];
 	devpriv->last_ctreg = -1;	/* force ctreg update */
 
@@ -237,10 +235,8 @@ static int adq12b_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 		s->n_chan = 16;
 	}
 
-	if (devpriv->unipolar)
-		s->range_table = &range_adq12b_ai_unipolar;
-	else
-		s->range_table = &range_adq12b_ai_bipolar;
+	s->range_table = it->options[1] ? &range_adq12b_ai_unipolar
+					: &range_adq12b_ai_bipolar;
 
 	s->maxdata = 0xfff;