V4L/DVB (12948): v4l1-compat: fix VIDIOC_G_STD handling

The VIDIOC_G_STD ioctl may not be present in the case of radio receivers.
In that case G_STD will return an error. The v4l1-compat layer should not
attempt to propagate that error to the caller, instead it should be
ignored.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/v4l1-compat.c

@@ -564,10 +564,9 @@ static noinline long v4l1_compat_get_input_info(
 		break;
 	}
 	chan->norm = 0;
-	err = drv(file, VIDIOC_G_STD, &sid);
-	if (err < 0)
-		dprintk("VIDIOCGCHAN / VIDIOC_G_STD: %ld\n", err);
-	if (err == 0) {
+	/* Note: G_STD might not be present for radio receivers,
+	 * so we should ignore any errors. */
+	if (drv(file, VIDIOC_G_STD, &sid) == 0) {
 		if (sid & V4L2_STD_PAL)
 			chan->norm = VIDEO_MODE_PAL;
 		if (sid & V4L2_STD_NTSC)
@@ -776,10 +775,9 @@ static noinline long v4l1_compat_get_tuner(
 			tun->flags |= VIDEO_TUNER_SECAM;
 	}
 
-	err = drv(file, VIDIOC_G_STD, &sid);
-	if (err < 0)
-		dprintk("VIDIOCGTUNER / VIDIOC_G_STD: %ld\n", err);
-	if (err == 0) {
+	/* Note: G_STD might not be present for radio receivers,
+	 * so we should ignore any errors. */
+	if (drv(file, VIDIOC_G_STD, &sid) == 0) {
 		if (sid & V4L2_STD_PAL)
 			tun->mode = VIDEO_MODE_PAL;
 		if (sid & V4L2_STD_NTSC)