smp: Move secondary CPU initialization request

Do not assume that the scheduler selects the main processor for the
initialization thread.

cpukit/sapi/src/exinit.c

@@ -223,6 +223,10 @@ void rtems_initialize_start_multitasking(void)
 
   _System_state_Set( SYSTEM_STATE_BEGIN_MULTITASKING );
 
+#ifdef RTEMS_SMP
+  _SMP_Request_other_cores_to_perform_first_context_switch();
+#endif
+
   _Thread_Start_multitasking();
 
   /*******************************************************************