drm/msm/gpu: Check the status of registration to PM QoS

There is a need to check the returned value of the registration function.
In case of returned error, print that and stop the init process.

Fixes: 7c0ffcd ("drm/msm/gpu: Respect PM QoS constraints")
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Patchwork: https://patchwork.freedesktop.org/patch/620336/
Signed-off-by: Rob Clark <robdclark@chromium.org>

Author: lukaszluba-arm

drivers/gpu/drm/msm/msm_gpu_devfreq.c

@@ -140,6 +140,7 @@ void msm_devfreq_init(struct msm_gpu *gpu)
 {
 	struct msm_gpu_devfreq *df = &gpu->devfreq;
 	struct msm_drm_private *priv = gpu->dev->dev_private;
+	int ret;
 
 	/* We need target support to do devfreq */
 	if (!gpu->funcs->gpu_busy)
@@ -156,8 +157,12 @@ void msm_devfreq_init(struct msm_gpu *gpu)
 
 	mutex_init(&df->lock);
 
-	dev_pm_qos_add_request(&gpu->pdev->dev, &df->boost_freq,
-			       DEV_PM_QOS_MIN_FREQUENCY, 0);
+	ret = dev_pm_qos_add_request(&gpu->pdev->dev, &df->boost_freq,
+				     DEV_PM_QOS_MIN_FREQUENCY, 0);
+	if (ret < 0) {
+		DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize QoS\n");
+		return;
+	}
 
 	msm_devfreq_profile.initial_freq = gpu->fast_rate;