PCI: pciehp: Don't check adapter or latch status while disabling

It does not make much sense to refuse to disable a slot if an adapter is
not present or the latch is open. If an adapter is not present, it provides
an even better reason to disable the device slot.

This is specially a problem for link state hot-plug, because some ports use
in band mechanism for presence detection. Thus when link goes down,
presence detect also goes down. We _want_ that the removal should take
place in such case.

Thus remove the checks for adapter and latch in pciehp_disable_slot()

Signed-off-by: Rajat Jain <rajatxjain@gmail.com>
Signed-off-by: Rajat Jain <rajatjain@juniper.net>
Signed-off-by: Guenter Roeck <groeck@juniper.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>