V4L/DVB (13547): radio: add trivial checks on the tuner and type args.

Many radio drivers did not check the tuner and type field correctly
for g/s_frequency. These checks have now been added.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/radio/radio-mr800.c b/drivers/media/radio/radio-mr800.c
index 949f605..02a9cef 100644
--- a/drivers/media/radio/radio-mr800.c
+++ b/drivers/media/radio/radio-mr800.c
@@ -374,6 +374,8 @@
 {
 	struct amradio_device *radio = file->private_data;
 
+	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
+		return -EINVAL;
 	return amradio_setfreq(radio, f->frequency);
 }
 
@@ -383,6 +385,8 @@
 {
 	struct amradio_device *radio = file->private_data;
 
+	if (f->tuner != 0)
+		return -EINVAL;
 	f->type = V4L2_TUNER_RADIO;
 	f->frequency = radio->curfreq;