The VNBYTES() macro needs to have parentheses to prevent some (harmless)
macro expansion bugs.  The VNBYTES() macro is used like this:

	VID_TO_PIXEL(x) * VNBYTES(vid_priv->bpix)

The * operation is done before the / operation.  It still ends up with
the same results, but it's not ideal.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>