PCI: Deprecate pcim_iomap_regions() in favor of pcim_iomap_region()

pcim_iomap_regions() is a complicated function that uses a bit mask to
determine the BARs the user wishes to request and ioremap. Almost all users
only ever set a single bit in that mask, making that mechanism
questionable.

pcim_iomap_region() is now available as a more simple replacement.

Make pcim_iomap_region() a public function.

Mark pcim_iomap_regions() as deprecated.

Link: https://lore.kernel.org/r/20240807083018.8734-2-pstanner@redhat.com


Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>