Visibility of `aml::resource::IOPortDescriptor` members

[pjhades]

Hello! I need the information provided by aml::resource::IOPortDescriptor to do some device initialization. But its members are all private and I don't see any interface for accessing them. Can we make them (along with the members of other descriptor structs) public, like in aml::resource::IrqDescriptor? If that sounds reasonable I can open a PR.

[IsaacWoods]

Yep I think all of these should be public - this seems like an oversight on our part. Please do open a PR!