media: tuners/it913x.c: fix missing error code

Fixes this smatch warning:

drivers/media/tuners/it913x.c:65 it913x_init() warn: missing error code 'ret'

Set ret to -EINVAL if the clock identifier was invalid.
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/tuners/it913x.c

@@ -62,6 +62,7 @@ static int it913x_init(struct dvb_frontend *fe)
 		break;
 	default:
 		dev_err(&pdev->dev, "unknown clock identifier %d\n", utmp);
+		ret = -EINVAL;
 		goto err;
 	}