V4L/DVB (9911): em28xx: vidioc_try_fmt_vid_cap() doesn't need any lock

vidioc_try_fmt_vid_cap() just checks if a given resolution is supported.
It doesn't touch on struct em28xx device descriptor. so, there's no need
to lock.

While there, use unlikely() for those values that aren't likely to
occur.
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/em28xx/em28xx-video.c

@@ -732,17 +732,15 @@ static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
 	height &= 0xfffe;
 	width  &= 0xfffe;
 
-	if (height < 32)
+	if (unlikely(height < 32))
 		height = 32;
-	if (height > maxh)
+	if (unlikely(height > maxh))
 		height = maxh;
-	if (width < 48)
+	if (unlikely(width < 48))
 		width = 48;
-	if (width > maxw)
+	if (unlikely(width > maxw))
 		width = maxw;
 
-	mutex_lock(&dev->lock);
-
 	if (dev->board.is_em2800) {
 		/* the em2800 can only scale down to 50% */
 		if (height % (maxh / 2))
@@ -772,7 +770,6 @@ static int vidioc_try_fmt_vid_cap(struct file *file, void *priv,
 	f->fmt.pix.colorspace = V4L2_COLORSPACE_SMPTE170M;
 	f->fmt.pix.field = V4L2_FIELD_INTERLACED;
 
-	mutex_unlock(&dev->lock);
 	return 0;
 }