PCI: Use consistent controller Kconfig menu entry language

Use "PCIe controller" consistently instead of "host bridge", "bus driver",
etc.  Annotate with "(host mode)" or "(endpoint mode)" as needed.

Link: https://lore.kernel.org/r/20230418174336.145585-5-helgaas@kernel.org


Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>