drm/msm/gpu: Drop qos request if devm_devfreq_add_device() fails

In the event that devm_devfreq_add_device() fails the device's qos freq
list is left referencing df->idle_freq and df->boost_freq. Attempting to
initialize devfreq again after a probe deferral will then cause invalid
memory accesses in dev_pm_qos_add_request().

Fix this by dropping the requests in the error path.

Fixes: 7c0ffcd40b16 ("drm/msm/gpu: Respect PM QoS constraints")
Signed-off-by: Bjorn Andersson <[e-mail]>
Reviewed-by: Rob Clark <[e-mail]>
Reviewed-by: Dmitry Baryshkov <[e-mail]>
Patchwork: https://patchwork.freedesktop.org/patch/493001/
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Rob Clark <[e-mail]>

drivers/gpu/drm/msm/msm_gpu_devfreq.c

···
 
 	if (IS_ERR(df->devfreq)) {
 		DRM_DEV_ERROR(&gpu->pdev->dev, "Couldn't initialize GPU devfreq\n");
+		dev_pm_qos_remove_request(&df->idle_freq);
+		dev_pm_qos_remove_request(&df->boost_freq);
 		df->devfreq = NULL;
 		return;
 	}