Qt: Re-enable sync for multiplayer windows that aren't connected (fixes #2974)

CHANGES

@@ -13,6 +13,7 @@ Emulation fixes:
  - GBA SIO: Fix normal mode SI/SO semantics (fixes mgba.io/i/2925)
 Other fixes:
  - mGUI: Fix cases where an older save state screenshot would be shown (fixes mgba.io/i/2183)
+ - Qt: Re-enable sync for multiplayer windows that aren't connected (fixes mgba.io/i/2974)
 Misc:
  - Qt: Add exporting of SAV + RTC saves from Save Converter to strip RTC data
 

src/platform/qt/MultiplayerController.cpp

@@ -102,6 +102,10 @@ MultiplayerController::MultiplayerController() {
 			if (!id) {
 				for (int i = 1; i < controller->m_players.count(); ++i) {
 					player = controller->player(i);
+					if (player->node.gba->d.p->mode > SIO_MULTI) {
+						player->controller->setSync(true);
+						continue;
+					}
 					player->controller->setSync(false);
 					player->cyclesPosted += cycles;
 					if (player->awake < 1) {