PCI: Apply _HPX Link Control settings to all devices with a link

Previously we applied _HPX type 2 record Link Control register settings
only to bridges with a subordinate bus.  But it's better to apply them to
all devices with a link because if the subordinate bus has not been
allocated yet, we won't apply settings to the device.

Use pcie_cap_has_lnkctl() to determine whether the device has a Link
Control register instead of looking at dev->subordinate.

[bhelgaas: changelog]
Fixes: 6cd33649 ("PCI: Add pci_configure_device() during enumeration")
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>