drm/nouveau: handle -EACCES runtime PM return code

pm_runtime_get*() may return -EACCES to indicate a device does not have
runtime PM enabled. This is currently the case with platform devices
on Nouveau, and is not an error in that context. Handle this case
without failure.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/dispnv04/crtc.c

@@ -1048,7 +1048,7 @@ nouveau_crtc_set_config(struct drm_mode_set *set)
 
 	/* get a pm reference here */
 	ret = pm_runtime_get_sync(dev->dev);
-	if (ret < 0)
+	if (ret < 0 && ret != -EACCES)
 		return ret;
 
 	ret = drm_crtc_helper_set_config(set);

drivers/gpu/drm/nouveau/nouveau_connector.c

@@ -255,7 +255,7 @@ nouveau_connector_detect(struct drm_connector *connector, bool force)
 	}
 
 	ret = pm_runtime_get_sync(connector->dev->dev);
-	if (ret < 0)
+	if (ret < 0 && ret != -EACCES)
 		return conn_status;
 
 	i2c = nouveau_connector_ddc_detect(connector, &nv_encoder);

drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -679,7 +679,7 @@ nouveau_drm_open(struct drm_device *dev, struct drm_file *fpriv)
 
 	/* need to bring up power immediately if opening device */
 	ret = pm_runtime_get_sync(dev->dev);
-	if (ret < 0)
+	if (ret < 0 && ret != -EACCES)
 		return ret;
 
 	get_task_comm(tmpname, current);
@@ -762,7 +762,7 @@ long nouveau_drm_ioctl(struct file *filp,
 	dev = file_priv->minor->dev;
 
 	ret = pm_runtime_get_sync(dev->dev);
-	if (ret < 0)
+	if (ret < 0 && ret != -EACCES)
 		return ret;
 
 	ret = drm_ioctl(filp, cmd, arg);