PCI: Unify device inaccessible

Bring surprise removals and permanent failures together so we no longer
need separate flags.  The implementation enforces that error handling will
not be able to override a surprise removal's permanent channel failure.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>