[media] ttusb-dec: constify ttusbdecfe_config structure

The ttusbdecfe_config structure is never modified, so declare it
as const.

Other references to this structure type were already declared as const.

Done with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/usb/ttusb-dec/ttusb_dec.c

@@ -1606,7 +1606,7 @@ static int fe_send_command(struct dvb_frontend* fe, const u8 command,
 	return ttusb_dec_send_command(dec, command, param_length, params, result_length, cmd_result);
 }
 
-static struct ttusbdecfe_config fe_config = {
+static const struct ttusbdecfe_config fe_config = {
 	.send_command = fe_send_command
 };