Drop unused headers. No functional changes intended.

Style and cosmetic changes. No binary changes intended.

PCI Extended Configuration stuff written by nonaka@:
- Add PCI Extended Configuration Space support into x86.
- Check register offset of pci_conf_read() in MD part. It returns (pcireg_t)-1
if it isn't accessible.
- Decode Extended Capability in PCI Extended Configuration Space.
Currently the following extended capabilities are decoded:
- Advanced Error Reporting
- Virtual Channel
- Device Serial Number
- Power Budgeting
- Root Complex Link Declaration
- Root Complex Event Collector Association
- Access Control Services
- Alternative Routing-ID Interpretation
- Address Translation Services
- Single Root IO Virtualization
- Page Request
- TPH Requester
- Latency Tolerance Reporting
- Secondary PCI Express
- Process Address Space ID
- LN Requester
- L1 PM Substates
The following extended capabilities are not decoded yet:
- Root Complex Internal Link Control
- Multi-Function Virtual Channel
- RCRB Header
- Vendor Unique
- Configuration Access Correction
- Multiple Root IO Virtualization
- Multicast
- Resizable BAR
- Dynamic Power Allocation
- Protocol Multiplexing
- Downstream Port Containment
- Precision Time Management
- M-PCIe
- Function Reading Status Queueing
- Readiness Time Reporting
- Designated Vendor-Specific

branches: 1.4.12; 1.4.30;
Use <sys/foo.h> instead of <machine/foo.h> if such a file exists.
Don't assume <sys/cpu.h> includes <powerpc/subarch/cpu*.h>. Include it
explicitly.

struct device * -> device_t
struct cfdata * -> cfdata_t
split device/softc (CFATTACH_DECL_NEW)
use device_accessors and device_private
constify

branches: 1.2.32;
Remove clause 3 and 4 from TNF licenses

branches: 1.1.2; 1.1.4; 1.1.8; 1.1.10; 1.1.24; 1.1.26; 1.1.28;
Add a bunch of fixes and minor rewrites to ofppc to bring it closer to
working properly. This is still a work in progress, and all work so far
has been based on the PegasosII machne.

1) Rewrite how the ISA memory and IO space maps are found. More work
will still need to be done in this area.
2) Add a new OFW method of pci configuration. So far I can only get this
to work on the primary PCI bus on the Pegasos. Unsure if this is a
pegasos bug or a code bug.
3) Add the rtas device to ofppc, and add an "rtas_reboot" function to
rtas to allow me to reboot the PegasosII. The rtas driver works, and is
a great start but needs to be changed slightly to allow easier access to
the functions from outside the driver.
4) Fix a number of bugs that existed in the shared PCI code for ofw that
probably weren't tickled by macppc.

There is much much more left to do here, this is all still a work in
progress, but this commit will allow other people to play around with the
code if they want to.