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-maestro.c b/drivers/media/radio/radio-maestro.c
index 64d737c..f8213b7 100644
--- a/drivers/media/radio/radio-maestro.c
+++ b/drivers/media/radio/radio-maestro.c
@@ -200,6 +200,8 @@
 {
 	struct maestro *dev = video_drvdata(file);
 
+	if (f->tuner != 0 || f->type != V4L2_TUNER_RADIO)
+		return -EINVAL;
 	if (f->frequency < FREQ_LO || f->frequency > FREQ_HI)
 		return -EINVAL;
 	mutex_lock(&dev->lock);
@@ -213,6 +215,8 @@
 {
 	struct maestro *dev = video_drvdata(file);
 
+	if (f->tuner != 0)
+		return -EINVAL;
 	f->type = V4L2_TUNER_RADIO;
 	mutex_lock(&dev->lock);
 	f->frequency = BITS2FREQ(radio_bits_get(dev));