libchip: SMP support for NS16550
bsps/powerpc: SMP support for SPR functions

These registers are local to a processor, there is no need to use SMP
locks here.
bsp/qoriq: SMP support for IRQ support
score: Critical fix for SMP

The _Scheduler_SMP_Allocate_processor() and _Thread_Dispatch() exchange
information without locks.  Make sure we use the right load/store
ordering.
score: Documentation