drm/i915: Make 308 and 671 MHz cdclks more accurate on SKL

The SKL 308.57 MHz cdclk is probably 8640/28 = ~308.571 Mhz.
Similartly the 617.14 MHz cdclk is probably 8640/14 = ~617.143 MHz.
Let's use the slightly more accurate numbers. Potentially we might
change to computing all of these based on dividers, but let's
stick to the current theme for now..

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463172100-24715-13-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>

drivers/gpu/drm/i915/intel_display.c

@@ -5204,13 +5204,13 @@ static void intel_update_max_cdclk(struct drm_device *dev)
 		 * if the preferred vco is 8100 instead.
 		 */
 		if (limit == SKL_DFSM_CDCLK_LIMIT_675)
-			max_cdclk = 617140;
+			max_cdclk = 617143;
 		else if (limit == SKL_DFSM_CDCLK_LIMIT_540)
 			max_cdclk = 540000;
 		else if (limit == SKL_DFSM_CDCLK_LIMIT_450)
 			max_cdclk = 432000;
 		else
-			max_cdclk = 308570;
+			max_cdclk = 308571;
 
 		dev_priv->max_cdclk_freq = skl_calc_cdclk(max_cdclk, vco);
 	} else if (IS_BROXTON(dev)) {
@@ -5438,13 +5438,13 @@ static int skl_calc_cdclk(int max_pixclk, int vco)
 {
 	if (vco == 8640) {
 		if (max_pixclk > 540000)
-			return 617140;
+			return 617143;
 		else if (max_pixclk > 432000)
 			return 540000;
-		else if (max_pixclk > 308570)
+		else if (max_pixclk > 308571)
 			return 432000;
 		else
-			return 308570;
+			return 308571;
 	} else {
 		/* VCO 8100 */
 		if (max_pixclk > 540000)
@@ -5616,13 +5616,13 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv, int cdclk, int vco)
 		freq_select = CDCLK_FREQ_540;
 		pcu_ack = 2;
 		break;
-	case 308570:
+	case 308571:
 	case 337500:
 	default:
 		freq_select = CDCLK_FREQ_337_308;
 		pcu_ack = 0;
 		break;
-	case 617140:
+	case 617143:
 	case 675000:
 		freq_select = CDCLK_FREQ_675_617;
 		pcu_ack = 3;
@@ -6582,11 +6582,11 @@ static int skylake_get_display_clock_speed(struct drm_device *dev)
 		case CDCLK_FREQ_450_432:
 			return 432000;
 		case CDCLK_FREQ_337_308:
-			return 308570;
+			return 308571;
 		case CDCLK_FREQ_540:
 			return 540000;
 		case CDCLK_FREQ_675_617:
-			return 617140;
+			return 617143;
 		default:
 			MISSING_CASE(cdctl & CDCLK_FREQ_SEL_MASK);
 		}