ACPI: custom_method: remove meaningless null check before debugfs_remove()

debugfs_remove() has taken null pointer into account. So it is safe
to remove the check before debugfs_remove().
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/custom_method.c

@@ -92,8 +92,7 @@ static int __init acpi_custom_method_init(void)
 
 static void __exit acpi_custom_method_exit(void)
 {
-	if (cm_dentry)
-		debugfs_remove(cm_dentry);
+	debugfs_remove(cm_dentry);
 }
 
 module_init(acpi_custom_method_init);