PCI hotplug: fix memory leaks

Stanse found a cut&pasted memory leak in pciehp_queue_pushbutton_work
and shpchp_queue_pushbutton_work. info is not freed/assigned on all
paths. Fix that.

Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>