drm/i915: Add eDP intermediate frequencies for CHV

"P1273_DPLL_Programming Spreadsheet.xlsm" lists a boatload of
frequencies for eDP. Try to use them all.

For now I've decided not to add hardcoded DPLL dividers for these cases
since chv_find_best_dpll() works just fine.

I've not actually tested any of these since I don't have an eDP 1.4 panel.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Sonika Jindal <sonika.jindal@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -87,6 +87,9 @@ static const struct dp_link_dpll chv_dpll[] = {
 /* Skylake supports following rates */
 static const int gen9_rates[] = { 162000, 216000, 270000,
 				  324000, 432000, 540000 };
+static const int chv_rates[] = { 162000, 202500, 210000, 216000,
+				 243000, 270000, 324000, 405000,
+				 420000, 432000, 540000 };
 static const int default_rates[] = { 162000, 270000, 540000 };
 
 /**
@@ -1148,6 +1151,9 @@ intel_dp_source_rates(struct drm_device *dev, const int **source_rates)
 	if (INTEL_INFO(dev)->gen >= 9) {
 		*source_rates = gen9_rates;
 		return ARRAY_SIZE(gen9_rates);
+	} else if (IS_CHERRYVIEW(dev)) {
+		*source_rates = chv_rates;
+		return ARRAY_SIZE(chv_rates);
 	}
 
 	*source_rates = default_rates;