Rename iproc_pcie_pltfm_* to iproc_pltfm_pcie_* for consistency with other
drivers.  No functional change intended.

Link: https://lore.kernel.org/r/20211223011054.1227810-13-helgaas@kernel.orgSigned-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>