eeepc-laptop: fix device reference count leakage in eeepc_rfkill_hotplug()

Fix a device reference count leakage issue in function
eeepc_rfkill_hotplug().

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Matthew Garrett <mjg@redhat.com>