Pulseaudio: Debug print if we are in main thread

As documentation says:
  This function may not be called inside the event loop thread.
  Events that are dispatched from the event loop thread are
  executed with this lock held.

Add small debug print that makes sure that future code won't be
calling it from main thread.

src/hostapi/pulseaudio/pa_linux_pulseaudio_cb.c

@@ -158,6 +158,12 @@ void PaPulseAudio_Lock( pa_threaded_mainloop *mainloop )
     if( !pa_threaded_mainloop_in_thread( mainloop ) ) {
         pa_threaded_mainloop_lock( mainloop );
     }
+    else
+    {
+        PA_DEBUG( ("Portaudio %s: Called from event loop thread as value is: %d (not locked)\n",
+            __FUNCTION__,
+            pa_threaded_mainloop_in_thread( mainloop )) );
+    }
 }
 
 /* unlocks the Pulse Main loop when not called from it */
@@ -166,6 +172,12 @@ void PaPulseAudio_UnLock( pa_threaded_mainloop *mainloop )
     if( !pa_threaded_mainloop_in_thread( mainloop ) ) {
         pa_threaded_mainloop_unlock( mainloop );
     }
+    else
+    {
+        PA_DEBUG( ("Portaudio %s: Called from event loop thread as value is: %d (not unlocked)\n",
+            __FUNCTION__,
+            pa_threaded_mainloop_in_thread( mainloop )) );
+    }
 }
 
 void _PaPulseAudio_WriteRingBuffer( PaUtilRingBuffer *ringbuffer,