hp-wmi: remove double free caused by merge conflict

Commit 3e9b988e
"wmi: Free the allocated acpi objects through wmi_get_event_data"
had the same purpose as commit
44ef00e6
"hp-wmi: Fix two memleaks"

This should solve this regression:

http://bugzilla.kernel.org/show_bug.cgi?id=14890



Signed-off-by: Anisse Astier <anisse@astier.eu>
Reported-by: Sedat Dilek <sedat.dilek@googlemail.com>
Signed-off-by: Len Brown <len.brown@intel.com>