workaround osx compilation issue

Change-Id: I72cfab7efac104b93dfc8669a7c6cca1624008d1

Author: rdementi

src/topologyentry.h

@@ -6,6 +6,8 @@
 #include "types.h"
 #ifndef USER_KERNEL_SHARED
 #include "debug.h"
+#else
+#define DBG(x)
 #endif
 
 namespace pcm