drm/i915/cnl: Fix DDI hdmi level selection.

Let's get a proper HDMI DDI entry level for vswing programming
sequences on CNL.

Spec doesn't specify any default for HDMI tables,
so let's pick the last entry as the default for now.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170829232230.23051-7-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/intel_ddi.c

@@ -660,7 +660,10 @@ static int intel_ddi_hdmi_level(struct drm_i915_private *dev_priv, enum port por
 	if (IS_GEN9_LP(dev_priv))
 		return hdmi_level;
 
-	if (IS_GEN9_BC(dev_priv)) {
+	if (IS_CANNONLAKE(dev_priv)) {
+		cnl_get_buf_trans_hdmi(dev_priv, &n_hdmi_entries);
+		hdmi_default_entry = n_hdmi_entries - 1;
+	} else if (IS_GEN9_BC(dev_priv)) {
 		skl_get_buf_trans_hdmi(dev_priv, &n_hdmi_entries);
 		hdmi_default_entry = 8;
 	} else if (IS_BROADWELL(dev_priv)) {