PCI: pciehp: Remove pci_configure_slot() usage

We now configure each PCI device as it is enumerated, in pci_device_add(),
so remove the configuration done in pciehp.

That configuration, in pci_configure_device(), does not include the
MPS/MRRS configuration done by pcie_bus_configure_settings(), so keep
that here.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>