Patch from Bjorn Helgaas

PNP ports tend to be built-in, and discovering them after
PCI ports means the names of the built-in ports can change
if you add or remove PCI ports.

(And yes, we should look at getting rid of 8250_acpi.c
now that we have PNPACPI, but that's for another patch.)

Signed-off-by: Bjorn Helgaas