android: Stop updating fps counter when emulation stops

src/android/app/src/main/java/org/yuzu/yuzu_emu/fragments/EmulationFragment.kt

@@ -168,8 +168,11 @@ class EmulationFragment : Fragment(), SurfaceHolder.Callback, Choreographer.Fram
                 if (perfStats[FPS] > 0) {
                     binding.showFpsText.text = String.format("FPS: %.1f", perfStats[FPS])
                 }
+
+                if (!emulationState.isStopped) {
                     perfStatsUpdateHandler.postDelayed(perfStatsUpdater!!, 100)
                 }
+            }
             perfStatsUpdateHandler.post(perfStatsUpdater!!)
             binding.showFpsText.visibility = View.VISIBLE
         } else {