PCI: Protect restore with device lock to be consistent

Commit b014e96d ("PCI: Protect pci_error_handlers->reset_notify() usage
with device_lock()") added protection around pci_dev_restore() function so
a device-specific remove callback does not cause a race condition with
hotplug.

pci_dev_lock() usage has been forgotten in two places.  Add locks for
pci_slot_restore() and moving pci_dev_restore() inside the locks for
pci_try_reset_function().

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>