V4L/DVB (7462): bttv: Fix some API non-compliances for some audio/input V4L2 calls

Thanks to Cyrill Gorcunov <gorcunov@gmail.com> for pointing this
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/bt8xx/bttv-driver.c

@@ -3117,12 +3117,18 @@ static int bttv_s_crop(struct file *file, void *f, struct v4l2_crop *crop)
 
 static int bttv_g_audio(struct file *file, void *priv, struct v4l2_audio *a)
 {
+	if (unlikely(a->index))
+		return -EINVAL;
+
 	strcpy(a->name, "audio");
 	return 0;
 }
 
 static int bttv_s_audio(struct file *file, void *priv, struct v4l2_audio *a)
 {
+	if (unlikely(a->index))
+		return -EINVAL;
+
 	return 0;
 }
 
@@ -3518,10 +3524,9 @@ static int radio_enum_input(struct file *file, void *priv,
 static int radio_g_audio(struct file *file, void *priv,
 					struct v4l2_audio *a)
 {
-	if (a->index != 0)
+	if (unlikely(a->index))
 		return -EINVAL;
 
-	memset(a, 0, sizeof(*a));
 	strcpy(a->name, "Radio");
 
 	return 0;
@@ -3543,11 +3548,17 @@ static int radio_s_tuner(struct file *file, void *priv,
 static int radio_s_audio(struct file *file, void *priv,
 					struct v4l2_audio *a)
 {
+	if (unlikely(a->index))
+		return -EINVAL;
+
 	return 0;
 }
 
 static int radio_s_input(struct file *filp, void *priv, unsigned int i)
 {
+	if (unlikely(i))
+		return -EINVAL;
+
 	return 0;
 }