PCI/AER: Honor "pcie_ports=native" even if HEST sets FIRMWARE_FIRST

According to the documentation, "pcie_ports=native", linux should use
native AER and DPC services.  While that is true for the _OSC method
parsing, this is not the only place that is checked.  Should the HEST
list PCIe ports as firmware-first, linux will not use native services.

This happens because aer_acpi_firmware_first() doesn't take 'pcie_ports'
into account.  This is wrong.  DPC uses the same logic when it decides
whether to load or not, so fixing this also fixes DPC not loading.

Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
[bhelgaas: return "false" from bool function (from kbuild robot)]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>