cx231xx: don't return error on success

commit 1871d718 upstream.

The cx231xx_set_agc_analog_digital_mux_select() callers
expect it to return 0 or an error. Returning a positive value
makes the first attempt to switch between analog/digital to fail.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/media/video/cx231xx/cx231xx-avcore.c

@@ -1264,7 +1264,10 @@ int cx231xx_set_agc_analog_digital_mux_select(struct cx231xx *dev,
 				   dev->board.agc_analog_digital_select_gpio,
 				   analog_or_digital);
 
-	return status;
+	if (status < 0)
+		return status;
+
+	return 0;
 }
 
 int cx231xx_enable_i2c_port_3(struct cx231xx *dev, bool is_port_3)