drm/i915: Disable LVDS on Radiant P845

Radiant P845 does not have LVDS, only VGA.

Cc: stable@vger.kernel.org
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105468


Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180309222204.4771-1-linux@rainbow-software.org