pci/x86: Reimplement PCIe configuration mechanism using ECAM.

This allows us to drop the PCI-specific ACPI management entirely.
Confirmed working on x86, and the fallbacks when there is no ACPI
also still work.

Change-Id: I6dac9f5539f99b934b17b341634ce22628bc66fd
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6470
Reviewed-by: X512 <danger_mail@list.ru>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

bus_managers/pci: split PCI controller to separate add-on

busses/pci/x86: add
Other add-ons are in following commits.

Change-Id: I7a77bfaef0e8995917b4b54c8369d7075533ec26
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6220
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>