Bring up changes from nuttx/pci branch

[raiden00pl]

Summary

This is work from nuttx pci branch from @sonicyang with my cosmetic changes and squashing related commits.
I'll start working on PCIE soon and these commits will be the basis for my work.
This PR doesn't contain 9a36544 because I'll rewrite it as common logic for Intel64

Impact

Testing

CI

[btashton]

Looks like my changes may have gotten dropped? I made quite a few fixes around the PCI stuff to the point were I was able to use it on my laptop and enumerate real devices. Let me see if I can find this.

[btashton]

Here it is https://github.com/btashton/incubator-nuttx/commits/pci-btashton/
It contains quite a bit of code on top of what is here that is both bug fixes and implementation extensions.

[acassis]

@btashton is it possible to send the improvements you made on top of this commit? It should be very useful case we could get NuttX booting on real x84_64 with PCIe support!

[btashton]

I don't think this branch in the PR is ready to merge given the issues that were resolved. Why not pull these changes in?

[xiaoxiang781216]

@raiden00pl we are developing a pcie driver framework, which may better than this one.

[raiden00pl]

Looks like my changes may have gotten dropped? I made quite a few fixes around the PCI stuff to the point were I was able to use it on my laptop and enumerate real devices. Let me see if I can find this.

THB, this is the first time I see your https://github.com/btashton/incubator-nuttx/commits/pci-btashton/ branch and these commits where not included on nuttx/pci branch. I'll be happy to include these changes.

@raiden00pl we are developing a pcie driver framework, which may better than this one.

@xiaoxiang781216 do you have any plans to add this to the upstream in the near future?

[xiaoxiang781216]

Yes, it will upstream once it's mature in the next couple month.

[raiden00pl]

@xiaoxiang781216 what do you think about applying this pcie implementation first (with the changes from Brennan included). When your implementation goes upstream we can mark this work as legacy, port what is needed to the new version and when everything is ported, remove the legacy version.

[xiaoxiang781216]

Sure.