Savestate: Reset what older states lack instead of keeping pre-load values

Missing sections (videocodec, audiocodec, aac, mp3) and old-version
branches (impose, io, umd, gps, mic, display, font) left the session
before the load in place.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Core/HLE/sceDisplay.cpp

@@ -299,6 +299,10 @@ void __DisplayDoState(PointerWrap &p) {
 		Do(p, lastFlipCycles);
 		Do(p, nextFlipCycles);
 	}
+	if (p.mode == p.MODE_READ) {
+		// Not saved. Start counting again rather than carry over the session before the load.
+		lastFlipsTooFrequent = 0;
+	}
 
 	gpu->DoState(p);