drm/i915: split clock gating init into per-chipset functions

This helps contain the mess to init_display() instead.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/i915_drv.h

@@ -209,12 +209,12 @@ struct drm_i915_display_funcs {
 			     int x, int y,
 			     struct drm_framebuffer *old_fb);
 	void (*fdi_link_train)(struct drm_crtc *crtc);
+	void (*init_clock_gating)(struct drm_device *dev);
 	/* clock updates for mode set */
 	/* cursor updates */
 	/* render clock increase/decrease */
 	/* display clock increase/decrease */
 	/* pll clock increase/decrease */
-	/* clock gating init */
 };
 
 struct intel_device_info {

drivers/gpu/drm/i915/i915_suspend.c

@@ -864,7 +864,7 @@ int i915_restore_state(struct drm_device *dev)
 	}
 
 	/* Clock gating state */
-	intel_enable_clock_gating(dev);
+	dev_priv->display.init_clock_gating(dev);
 
 	if (IS_IRONLAKE_M(dev)) {
 		ironlake_enable_drps(dev);