[media] cx231xx: add addr for demod and make i2c_devs const

I2C address 0x10 is the demod. While here, make the array const.
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/cx231xx/cx231xx-i2c.c

@@ -471,7 +471,8 @@ static struct i2c_adapter cx231xx_adap_template = {
  * i2c_devs
  * incomplete list of known devices
  */
-static char *i2c_devs[128] = {
+static const char *i2c_devs[128] = {
+	[0x20 >> 1] = "demod",
 	[0x60 >> 1] = "colibri",
 	[0x88 >> 1] = "hammerhead",
 	[0x8e >> 1] = "CIR",