Add Hotkeys for Skylanders Portal and Infinity Base Menus

Adds two new hotkeys to open the menus for emulated USB devices- Skylanders Portal of Power and the Infinity Base. (Hotkeys only active when game is running).

Portal menu: Default is <Ctrl+P>.
Infinity base: Default is <Ctrl+I>

Source/Core/DolphinQt/HotkeyScheduler.h

@@ -65,6 +65,9 @@ signals:
   void ToggleBreakpoint();
   void AddBreakpoint();
 
+  void SkylandersPortalHotkey();
+  void InfinityBaseHotkey();
+
 private:
   void Run();
   void CheckDebuggingHotkeys();