core: optimized output on kernel-init

This PR saves some memory by ommiting redundant output. The printing
of "jumpint into first task..." is obsolete, as the thread_create
calls are not checked for errors anymore.

Further the version print is moved into the main_trampoline. This
prevents the STDLIB from using precious stack space on the ISR
stack, on which it is running before jumping into main - hence
opening the option to decrease the stacksize for the ISR stack.

core/kernel_init.c

@@ -51,6 +51,8 @@ static void *main_trampoline(void *arg)
     auto_init();
 #endif
 
+    LOG_INFO("main(): This is RIOT! (Version: " RIOT_VERSION ")\n");
+
     main();
     return NULL;
 }
@@ -82,7 +84,6 @@ static char idle_stack[THREAD_STACKSIZE_IDLE];
 void kernel_init(void)
 {
     (void) disableIRQ();
-    LOG_INFO("kernel_init(): This is RIOT! (Version: %s)\n", RIOT_VERSION);
 
     hwtimer_init();
 
@@ -96,7 +97,5 @@ void kernel_init(void)
             CREATE_WOUT_YIELD | CREATE_STACKTEST,
             main_trampoline, NULL, main_name);
 
-    LOG_INFO("kernel_init(): jumping into first task...\n");
-
     cpu_switch_context_exit();
 }