Limit reporting of GPU_ONLY signal waits from host.

Such waits must spin but are functionally correct.

Change-Id: I4992852f04da788495c6f566c46a3dffaf38397c

runtime/hsa-runtime/core/runtime/default_signal.cpp

@@ -84,8 +84,8 @@ hsa_signal_value_t BusyWaitSignal::WaitRelaxed(hsa_signal_condition_t condition,
   bool condition_met = false;
   int64_t value;
 
-  debug_warning((!g_use_interrupt_wait || isIPC()) &&
-                "Use of non-host signal in host signal wait API.");
+  debug_warning_n((!g_use_interrupt_wait || isIPC()) &&
+                  "Use of non-host signal in host signal wait API.", 10);
 
   timer::fast_clock::time_point start_time, time;
   start_time = timer::fast_clock::now();