PCI/ERR: Fix uevent on failure to recover

Upon failure to recover from a PCIe error through AER, DPC or EDR, a
uevent is sent to inform user space about disconnection of the bridge
whose subordinate devices failed to recover.

However the bridge itself is not disconnected.  Instead, a uevent should
be sent for each of the subordinate devices.

Only if the "bridge" happens to be a Root Complex Event Collector or
Integrated Endpoint does it make sense to send a uevent for it (because
there are no subordinate devices).

Right now if there is a mix of subordinate devices with and without
pci_error_handlers, a BEGIN_RECOVERY event is sent for those with
pci_error_handlers but no FAILED_RECOVERY event is ever sent for them
afterwards.  Fix it.

Fixes: 856e1eb9 ("PCI/AER: Add uevents in AER and EEH error/resume")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org  # v4.16+
Link: https://patch.msgid.link/68fc527a380821b5d861dd554d2ce42cb739591c.1755008151.git.lukas@wunner.de