platform/x86: hp-bioscfg: Fix reference leak

If a duplicate attribute is found using kset_find_obj(), a reference
to that attribute is returned which needs to be disposed accordingly
using kobject_put(). Use kobject_put() to dispose the duplicate
attribute in such a case.
As a side note, a very similar bug was fixed in
commit 7295a996 ("platform/x86: dell-sysman: Fix reference leak"),
so it seems that the bug was copied from that driver.

Compile-tested only.

Fixes: a34fc329

 ("platform/x86: hp-bioscfg: bioscfg")
Suggested-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Reviewed-by: Jorge Lopez <jorge.lopez2@hp.com>
Link: https://lore.kernel.org/r/20230925142819.74525-3-W_Armin@gmx.de
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>