Add perf stat logging through ini setting

For better tracking of performance regressions on incoming changes, this
change adds a way to dump frametime to file by changing an ini config
option. This is intentionally hidden as its only useful to a small
number of individuals, and not really applicable to the general
userbase.

src/core/hle/service/gsp/gsp_gpu.cpp

@@ -307,7 +307,7 @@ ResultCode SetBufferSwap(u32 screen_id, const FrameBufferInfo& info) {
 
     if (screen_id == 0) {
         MicroProfileFlip();
-        Core::System::GetInstance().perf_stats.EndGameFrame();
+        Core::System::GetInstance().perf_stats->EndGameFrame();
     }
 
     return RESULT_SUCCESS;