drm/i915: define Haswell watermarks and clock gating

For now, we simple reuse the Ivy Bridge routines here.
Signed-off-by: NEugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -3685,6 +3685,17 @@ void intel_init_pm(struct drm_device *dev)
 			}
 			dev_priv->display.init_clock_gating = ivybridge_init_clock_gating;
 			dev_priv->display.sanitize_pm = gen6_sanitize_pm;
+		} else if (IS_HASWELL(dev)) {
+			if (SNB_READ_WM0_LATENCY()) {
+				dev_priv->display.update_wm = sandybridge_update_wm;
+				dev_priv->display.update_sprite_wm = sandybridge_update_sprite_wm;
+			} else {
+				DRM_DEBUG_KMS("Failed to read display plane latency. "
+					      "Disable CxSR\n");
+				dev_priv->display.update_wm = NULL;
+			}
+			dev_priv->display.init_clock_gating = ivybridge_init_clock_gating;
+			dev_priv->display.sanitize_pm = gen6_sanitize_pm;
 		} else
 			dev_priv->display.update_wm = NULL;
 	} else if (IS_VALLEYVIEW(dev)) {