clean up bounds checking for SIDEVICE_ENUM

Source/Core/Core/BootManager.cpp

@@ -287,7 +287,7 @@ bool BootCore(const std::string& _rFilename)
     {
       int source;
       controls_section->Get(StringFromFormat("PadType%u", i), &source, -1);
-      if (source >= (int)SIDEVICE_NONE && source <= (int)SIDEVICE_WIIU_ADAPTER)
+      if (source >= SIDEVICE_NONE && source < SIDEVICE_COUNT)
       {
         SConfig::GetInstance().m_SIDevice[i] = (SIDevices)source;
         config_cache.bSetPads[i] = true;

Source/Core/Core/HW/SI_Device.h

@@ -64,6 +64,8 @@ enum SIDevices : int
   SIDEVICE_GC_TARUKONGA,
   SIDEVICE_AM_BASEBOARD,
   SIDEVICE_WIIU_ADAPTER,
+  // not a valid device, used for checking whether enum value is valid
+  SIDEVICE_COUNT,
 };
 
 class ISIDevice