drm/tegra: Output cleanup functions cannot fail

The tegra_output_exit() and tegra_output_remove() functions cannot fail,
so make them return void.

Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/dsi.c b/drivers/gpu/drm/tegra/dsi.c
index 1401d0d..23f4b0f 100644
--- a/drivers/gpu/drm/tegra/dsi.c
+++ b/drivers/gpu/drm/tegra/dsi.c
@@ -1577,11 +1577,7 @@
 		return err;
 	}
 
-	err = tegra_output_remove(&dsi->output);
-	if (err < 0) {
-		dev_err(&pdev->dev, "failed to remove output: %d\n", err);
-		return err;
-	}
+	tegra_output_remove(&dsi->output);
 
 	mipi_dsi_host_unregister(&dsi->host);
 	tegra_mipi_free(dsi->mipi);