Staging: comedi: fl512: Simplify a trivial if-return sequence

This patch simplify a trivial if-return sequence. Possibly combine with
a preceding function call.
Signed-off-by: Abdul Hussain <habdul@visteon.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/fl512.c

@@ -136,11 +136,7 @@ static int fl512_attach(struct comedi_device *dev, struct comedi_devconfig *it)
 	s->range_table	= &range_fl512;
 	s->insn_write	= fl512_ao_insn_write;
 
-	ret = comedi_alloc_subdev_readback(s);
-	if (ret)
-		return ret;
-
-	return 0;
+	return comedi_alloc_subdev_readback(s);
 }
 
 static struct comedi_driver fl512_driver = {