platform/x86: think-lmi: Fix issues with duplicate attributes

On an AMD based Lenovo T14, I find that the module doesn't work at
all, and instead has a traceback with messages like:

```
sysfs: cannot create duplicate filename '/devices/virtual/firmware-attributes/thinklmi/attributes/Reserved'
```

Duplicate and reserved values showing up appear to be a firmware bug,
but they shouldn't make the driver explode.  So catch them and skip
them.

Fixes: a40cd7ef22 ("platform/x86: think-lmi: Add WMI interface support on Lenovo platforms")
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20210622200755.12379-2-mario.limonciello@amd.com
[hdegoede@redhat.com: Add missing kfree(tlmi_priv.setting[i])]
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/think-lmi.c

@@ -691,6 +691,17 @@ static int tlmi_sysfs_init(void)
 		if (!tlmi_priv.setting[i])
 			continue;
 
+		/* check for duplicate or reserved values */
+		if (kset_find_obj(tlmi_priv.attribute_kset, tlmi_priv.setting[i]->display_name) ||
+		    !strcmp(tlmi_priv.setting[i]->display_name, "Reserved")) {
+			pr_debug("duplicate or reserved attribute name found - %s\n",
+				tlmi_priv.setting[i]->display_name);
+			kfree(tlmi_priv.setting[i]->possible_values);
+			kfree(tlmi_priv.setting[i]);
+			tlmi_priv.setting[i] = NULL;
+			continue;
+		}
+
 		/* Build attribute */
 		tlmi_priv.setting[i]->kobj.kset = tlmi_priv.attribute_kset;
 		ret = kobject_init_and_add(&tlmi_priv.setting[i]->kobj, &tlmi_attr_setting_ktype,