sparc: Use __leon__ multilib define
score: Add _Per_CPU_Get_snapshot()
score: SMP initialization changes

Add and use _CPU_SMP_Start_processor().  Add and use
_CPU_SMP_Finalize_initialization().  This makes most
_CPU_SMP_Initialize() functions a bit simpler since we can calculate the
minimum value of the count of processors requested by the application
configuration and the count of physically or virtually available
processors in the high-level code.

The CPU port has now the ability to signal a processor start failure.
With the support for clustered/partitioned scheduling the presence of
particular processors can be configured to be optional or mandatory.
There will be a fatal error only in case mandatory processors are not
present.

The CPU port may use a timeout to monitor the start of a processor.
capture: Use ISR lock for SMP support