platform/x86: dell-sysman: Fix reference leak

If a duplicate attribute is found using kset_find_obj(),
a reference to that attribute is returned. This means
that we need to dispose it accordingly. Use kobject_put()
to dispose the duplicate attribute in such a case.

Compile-tested only.

Fixes: e8a60aa7 ("platform/x86: Introduce support for Systems Management Driver over WMI for Dell Systems")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20230805053610.7106-1-W_Armin@gmx.deReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

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

@@ -393,6 +393,7 @@ static int init_bios_attributes(int attr_type, const char *guid)
 	struct kobject *attr_name_kobj; //individual attribute names
 	union acpi_object *obj = NULL;
 	union acpi_object *elements;
+	struct kobject *duplicate;
 	struct kset *tmp_set;
 	int min_elements;
 
@@ -451,9 +452,11 @@ static int init_bios_attributes(int attr_type, const char *guid)
 		else
 			tmp_set = wmi_priv.main_dir_kset;
 
-		if (kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer)) {
-			pr_debug("duplicate attribute name found - %s\n",
-				elements[ATTR_NAME].string.pointer);
+		duplicate = kset_find_obj(tmp_set, elements[ATTR_NAME].string.pointer);
+		if (duplicate) {
+			pr_debug("Duplicate attribute name found - %s\n",
+				 elements[ATTR_NAME].string.pointer);
+			kobject_put(duplicate);
 			goto nextobj;
 		}