video/hdmi: Derive the bar data valid bit from the bar data fields

Just like:

  Author: Damien Lespiau <damien.lespiau@intel.com>
  Date:   Mon Aug 12 11:53:24 2013 +0100

      video/hdmi: Don't let the user of this API create invalid infoframes

But this time for the horizontal/vertical bar data present bits.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>