System task initialization moved to main()

- the system task initialization code does not really need to be part
  of the system task process. An earlier initialization in kernel is
  cleaner as it does not only initialize the syscalls but also irq
  hooks etc.

kernel/main.c

@@ -210,6 +210,9 @@ PUBLIC void main()
   /* Architecture-dependent initialization. */
   arch_init();
 
+  /* System and processes initialization */
+  system_init();
+
 #if SPROFILE
   sprofiling = 0;      /* we're not profiling until instructed to */
 #endif /* SPROFILE */