PCI refactor
Created by: imp
This is first batch of commits laying the foundation for the more serious PCI work. It introduces only minor visible changes:
use drivers::pciconfig::PciConfig;
should be changed into
use drivers::pci::config::PciConfig;
All the rest of the external interfaces remain the same. Internally it moves everything under pci/ subdirectory and replaces numbers with PCI constants in PCI binding code.
More commits to generalize the PCI enumeration to follow