drm/msm: Fix error return code in msm_drm_init()

Fix to return a negative error code from the error handling case instead
of 0, as done elsewhere in this function.

Fixes: 7f9743ab ("drm/msm: validate display and event threads")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210508022836.1777-1-thunder.leizhen@huawei.comReviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/msm_drv.c

@@ -536,6 +536,7 @@ static int msm_drm_init(struct device *dev, const struct drm_driver *drv)
 		priv->event_thread[i].worker = kthread_create_worker(0,
 			"crtc_event:%d", priv->event_thread[i].crtc_id);
 		if (IS_ERR(priv->event_thread[i].worker)) {
+			ret = PTR_ERR(priv->event_thread[i].worker);
 			DRM_DEV_ERROR(dev, "failed to create crtc_event kthread\n");
 			goto err_msm_uninit;
 		}