platform/x86: dell-wmi-sysman: Make sysman_init() return -ENODEV of the interfaces are not found

When either the attributes or the password interface is not found, then
unregister the 2 wmi drivers again and return -ENODEV from sysman_init().

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Cc: Divya Bharathi <Divya_Bharathi@dell.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Reported-by: Alexander Naumann <alexandernaumann@gmx.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20210321115901.35072-7-hdegoede@redhat.com

drivers/platform/x86/dell/dell-wmi-sysman/sysman.c

@@ -506,15 +506,17 @@ static int __init sysman_init(void)
 	}
 
 	ret = init_bios_attr_set_interface();
-	if (ret || !wmi_priv.bios_attr_wdev) {
-		pr_debug("failed to initialize set interface\n");
+	if (ret)
 		return ret;
-	}
 
 	ret = init_bios_attr_pass_interface();
-	if (ret || !wmi_priv.password_attr_wdev) {
-		pr_debug("failed to initialize pass interface\n");
+	if (ret)
 		goto err_exit_bios_attr_set_interface;
+
+	if (!wmi_priv.bios_attr_wdev || !wmi_priv.password_attr_wdev) {
+		pr_debug("failed to find set or pass interface\n");
+		ret = -ENODEV;
+		goto err_exit_bios_attr_pass_interface;
 	}
 
 	ret = class_register(&firmware_attributes_class);