Extend the PIT driver to allow for one shot timers even though it
monotonically runs a 1kHz tick. This allows it to keep time and provide
one shot events, though only at 1ms resolution.
-Add a bus manager level, which is an object oriented walk of the pci
busses to build a per device object for later manipulation.
-Add features to enable MSI interrupts.
-Extend generic interrupt api to allow the platform to allocate vectors
for MSI interrupts.
-Rearrange a bit of the pc platform for the platform api changes.
-Add PC platform support for using the local apic to EOI MSI vectors.
-Fix up a few existing PCI drivers for small API changes.
-Add a few stubbed out routines for non PC platforms that use PCI.
