drm/tegra: debugfs cleanup cannot fail

The debugfs cleanup code never fails, so no error is returned. Therefore
the functions can all return void instead.

Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/sor.c b/drivers/gpu/drm/tegra/sor.c
index be1ad42..a1c16c5 100644
--- a/drivers/gpu/drm/tegra/sor.c
+++ b/drivers/gpu/drm/tegra/sor.c
@@ -710,12 +710,10 @@
 	return err;
 }
 
-static int tegra_sor_debugfs_exit(struct tegra_sor *sor)
+static void tegra_sor_debugfs_exit(struct tegra_sor *sor)
 {
 	debugfs_remove_recursive(sor->debugfs);
 	sor->debugfs = NULL;
-
-	return 0;
 }
 
 static void tegra_sor_connector_dpms(struct drm_connector *connector, int mode)
@@ -1410,11 +1408,8 @@
 	clk_disable_unprepare(sor->clk_dp);
 	clk_disable_unprepare(sor->clk);
 
-	if (IS_ENABLED(CONFIG_DEBUG_FS)) {
-		err = tegra_sor_debugfs_exit(sor);
-		if (err < 0)
-			dev_err(sor->dev, "debugfs cleanup failed: %d\n", err);
-	}
+	if (IS_ENABLED(CONFIG_DEBUG_FS))
+		tegra_sor_debugfs_exit(sor);
 
 	return 0;
 }