loader: Fix 32-bit loader exception when layers enabled for Vulkan apps.

The loader_create_device_terminator had an incorrect calling convention.  This
caused the ESP pointer to not get properly restored after the function was
called by a 32-bit application.
diff --git a/loader/loader.h b/loader/loader.h
index 6dcc5de..4f253ef 100644
--- a/loader/loader.h
+++ b/loader/loader.h
@@ -427,7 +427,7 @@
         VkPhysicalDevice physicalDevice,
         VkPhysicalDeviceMemoryProperties * pProperties);
 
-VkResult loader_create_device_terminator(
+VKAPI_ATTR VkResult VKAPI_CALL loader_create_device_terminator(
         VkPhysicalDevice                            physicalDevice,
         const VkDeviceCreateInfo*                   pCreateInfo,
         const VkAllocationCallbacks*                pAllocator,