LoongArch: Fix debugfs_create_dir() error checking

The debugfs_create_dir() returns ERR_PTR in case of an error and the
correct way of checking it is using the IS_ERR_OR_NULL inline function
rather than the simple null comparision. This patch fixes the issue.

Cc: stable@vger.kernel.org
Suggested-By: Ivan Orlov <ivan.orlov0322@gmail.com>
Signed-off-by: Immad Mir <mirimmad17@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/kernel/unaligned.c

@@ -485,7 +485,7 @@ static int __init debugfs_unaligned(void)
 	struct dentry *d;
 
 	d = debugfs_create_dir("loongarch", NULL);
-	if (!d)
+	if (IS_ERR_OR_NULL(d))
 		return -ENOMEM;
 
 	debugfs_create_u32("unaligned_instructions_user",