ACPICA: Fix possible fault in return package object repair code

Fixes a problem that can occur when a lone package object is
wrapped with an outer package object in order to conform to
the ACPI specification. Can affect these predefined names:
_ALR,_MLS,_PSS,_TRT,_TSS,_PRT,_HPX,_DLM,_CSD,_PSD,_TSD

https://bugzilla.kernel.org/show_bug.cgi?id=44171

This problem was introduced in 3.4-rc1 by commit
6a99b1c94d053b3420eaa4a4bc8b2883dd90a2f9
(ACPICA: Object repair code: Support to add Package wrappers)

Reported-by: Vlastimil Babka <caster@gentoo.org>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: <stable@vger.kernel.org> # 3.4
Signed-off-by: Len Brown <len.brown@intel.com>