drm/tilcdc: Register cpufreq notifier after we have initialized crtc

Register cpufreq notifier after we have initialized the crtc and
unregister it before we remove the ctrc. Receiving a cpufreq notify
without crtc causes a crash.
Reported-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Jyri Sarha <jsarha@ti.com>

drivers/gpu/drm/tilcdc/tilcdc_drv.c

@@ -184,6 +184,12 @@ static void tilcdc_fini(struct drm_device *dev)
 {
 	struct tilcdc_drm_private *priv = dev->dev_private;
 
+#ifdef CONFIG_CPU_FREQ
+	if (priv->freq_transition.notifier_call)
+		cpufreq_unregister_notifier(&priv->freq_transition,
+					    CPUFREQ_TRANSITION_NOTIFIER);
+#endif
+
 	if (priv->crtc)
 		tilcdc_crtc_shutdown(priv->crtc);
 
@@ -198,12 +204,6 @@ static void tilcdc_fini(struct drm_device *dev)
 	drm_mode_config_cleanup(dev);
 	tilcdc_remove_external_device(dev);
 
-#ifdef CONFIG_CPU_FREQ
-	if (priv->freq_transition.notifier_call)
-		cpufreq_unregister_notifier(&priv->freq_transition,
-					    CPUFREQ_TRANSITION_NOTIFIER);
-#endif
-
 	if (priv->clk)
 		clk_put(priv->clk);
 
@@ -274,17 +274,6 @@ static int tilcdc_init(struct drm_driver *ddrv, struct device *dev)
 		goto init_failed;
 	}
 
-#ifdef CONFIG_CPU_FREQ
-	priv->freq_transition.notifier_call = cpufreq_transition;
-	ret = cpufreq_register_notifier(&priv->freq_transition,
-			CPUFREQ_TRANSITION_NOTIFIER);
-	if (ret) {
-		dev_err(dev, "failed to register cpufreq notifier\n");
-		priv->freq_transition.notifier_call = NULL;
-		goto init_failed;
-	}
-#endif
-
 	if (of_property_read_u32(node, "max-bandwidth", &priv->max_bandwidth))
 		priv->max_bandwidth = TILCDC_DEFAULT_MAX_BANDWIDTH;
 
@@ -361,6 +350,17 @@ static int tilcdc_init(struct drm_driver *ddrv, struct device *dev)
 	}
 	modeset_init(ddev);
 
+#ifdef CONFIG_CPU_FREQ
+	priv->freq_transition.notifier_call = cpufreq_transition;
+	ret = cpufreq_register_notifier(&priv->freq_transition,
+			CPUFREQ_TRANSITION_NOTIFIER);
+	if (ret) {
+		dev_err(dev, "failed to register cpufreq notifier\n");
+		priv->freq_transition.notifier_call = NULL;
+		goto init_failed;
+	}
+#endif
+
 	if (priv->is_componentized) {
 		ret = component_bind_all(dev, ddev);
 		if (ret < 0)