[media] pvrusb2: get rid of warning: no previous prototype

drivers/media/usb/pvrusb2/pvrusb2-v4l2.c:199:5: warning: no previous prototype for 'pvr2_s_std' [-Wmissing-prototypes]
drivers/media/usb/pvrusb2/pvrusb2-v4l2.c:368:5: warning: no previous prototype for 'pvr2_s_frequency' [-Wmissing-prototypes]
Acked-by: Mike Isely <isely@pobox.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/usb/pvrusb2/pvrusb2-v4l2.c

@@ -196,7 +196,7 @@ static int pvr2_g_std(struct file *file, void *priv, v4l2_std_id *std)
 	return ret;
 }
 
-int pvr2_s_std(struct file *file, void *priv, v4l2_std_id *std)
+static int pvr2_s_std(struct file *file, void *priv, v4l2_std_id *std)
 {
 	struct pvr2_v4l2_fh *fh = file->private_data;
 	struct pvr2_hdw *hdw = fh->channel.mc_head->hdw;
@@ -365,7 +365,7 @@ static int pvr2_s_tuner(struct file *file, void *priv, struct v4l2_tuner *vt)
 			vt->audmode);
 }
 
-int pvr2_s_frequency(struct file *file, void *priv, struct v4l2_frequency *vf)
+static int pvr2_s_frequency(struct file *file, void *priv, struct v4l2_frequency *vf)
 {
 	struct pvr2_v4l2_fh *fh = file->private_data;
 	struct pvr2_hdw *hdw = fh->channel.mc_head->hdw;