PCI/PM: Move pci_dev_wait() definition earlier

Move the definition of pci_dev_wait() above pci_power_up() so that it can
be called from the latter with no change in functionality.  This is a pure
code move with no functional change.

Link: https://lore.kernel.org/r/20191120051743.23124-1-vidyas@nvidia.com


Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>