In case of failure, debugfs_create_dir() does not return NULL, but
an error pointer. Most incorrect error checks were fixed,but the
one in mbox_test_add_debugfs() was forgotten.

Signed-off-by: Wang Ming <machel@vivo.com>
---
 drivers/mailbox/mailbox-test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mailbox/mailbox-test.c b/drivers/mailbox/mailbox-test.c
index fc6a12a51b40..ae9861c57fb1 100644
--- a/drivers/mailbox/mailbox-test.c
+++ b/drivers/mailbox/mailbox-test.c
@@ -268,7 +268,7 @@ static int mbox_test_add_debugfs(struct platform_device *pdev,
 		return 0;
 
 	tdev->root_debugfs_dir = debugfs_create_dir(dev_name(&pdev->dev), NULL);
-	if (!tdev->root_debugfs_dir) {
+	if (IS_ERR(tdev->root_debugfs_dir)) {
 		dev_err(&pdev->dev, "Failed to create Mailbox debugfs\n");
 		return -EINVAL;
 	}
-- 
2.25.1