Enhance the CHRP/pSeries platform layer:

• Densely number CPUs to avoid systems with CPUs with very high ID numbers
• Always have the BSP be CPU 0 to avoid remnant brokenness with non-0 BSPs in other parts of the kernel.
• Improve parsing of the device tree CPU listings on SMT systems.
• Allow reboot via RTAS as well as OF for pSeries systems booted by FDT without functioning Open Firmware.

Obtained from: projects/powernv
MFC after: 3 weeks