PCI hotplug: shpchp: use generic pci_configure_slot()

Use the generic pci_configure_slot() rather than the SHPC-specific
program_fw_provided_values().

Unlike the previous SHPC-specific code, pci_configure_slot() programs PCIe
settings when an _HPX method provides them, so if it's possible to have an
SHPC-managed PCIe device, it can now be configured.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>