score: Add PER_CPU_DATA_NEED_INITIALIZATION()

Make the initialization of the per-CPU data optional.

Change license to BSD-2-Clause according to file history and
re-licensing agreement.

Update #3053.

cpukit/sapi/src/exinit.c

@@ -32,7 +32,6 @@
 #include <rtems/score/heap.h>
 #include <rtems/score/interr.h>
 #include <rtems/score/isr.h>
-#include <rtems/score/percpudata.h>
 #include <rtems/score/priority.h>
 #include <rtems/score/schedulerimpl.h>
 #include <rtems/score/smpimpl.h>
@@ -58,18 +57,6 @@ _Objects_Information_table[ OBJECTS_APIS_LAST + 1 ] = {
   &_POSIX_Objects[ 0 ]
 };
 
-RTEMS_LINKER_RWSET(
-  _Per_CPU_Data,
-#if defined(RTEMS_SMP)
-  /*
-   * In SMP configurations, prevent false cache line sharing of per-processor
-   * data with a proper alignment.
-   */
-  RTEMS_ALIGNED( CPU_CACHE_LINE_BYTES )
-#endif
-  char
-);
-
 static void rtems_initialize_data_structures(void)
 {
   /*