pci/shpc: more generic handle hot-unplug in shpc_slot_command()

pci/shpc: more generic handle hot-unplug in shpc_slot_command()

Free slot if both conditions (power-led = OFF and state = DISABLED)
becomes true regardless of the sequence. It is similar to how PCIe
hotplug works.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Reviewed-by: Anton Kuchin <antonkuchin@yandex-team.ru>
Message-Id: <20230216180356.156832-5-vsementsov@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>