Merge pull request #6660 from kaspar030/fix_native_thread_yield_higher

cpu: native: fix thread_yield_higher isr_is_in() case

cpu/native/native_cpu.c

@@ -225,7 +225,7 @@ void thread_yield_higher(void)
         irq_enable();
     }
     else {
-        isr_thread_yield();
+        sched_context_switch_request = 1;
     }
 }