base: Tag API methods to debug.hh

Change-Id: Ic4395f3594cbc156a2b678710a3ed4717ce87a81
Signed-off-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33257
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/base/debug.hh

@@ -134,10 +134,17 @@ void clearDebugFlag(const char *string);
 
 void dumpDebugFlags();
 
+/**
+ * \def DTRACE(x)
+ *
+ * @ingroup api_trace
+ * @{
+ */
 #if TRACING_ON
 #   define DTRACE(x) (Debug::x)
 #else // !TRACING_ON
 #   define DTRACE(x) (false)
 #endif  // TRACING_ON
+/** @} */ // end of api_trace
 
 #endif // __BASE_DEBUG_HH__