UI: Prevent self-powerdown check on load new game.

Sometimes, when loading a new game or dump while an existing one is
running, we'd detect the "powerdown" and force back to the menu.

This was a race condition.

UI/EmuScreen.cpp

@@ -420,6 +420,8 @@ void EmuScreen::sendMessage(const char *message, const char *value) {
 			PSP_Shutdown();
 			bootPending_ = true;
 			gamePath_ = value;
+			// Don't leave it on CORE_POWERDOWN, we'll sometimes aggressively bail.
+			Core_UpdateState(CORE_POWERUP);
 		}
 	} else if (!strcmp(message, "config_loaded")) {
 		// In case we need to position touch controls differently.