bug 14537: vkGetPhysicalDeviceImageFormatProperties doesn't express all limitations (WIP)

Use VkSampleCountFlagBits exclusively.  Note that it can be casted to integer.

https://cvs.khronos.org/bugzilla/show_bug.cgi?id=14537
diff --git a/loader/loader.h b/loader/loader.h
index 829b2d1..f356a79 100644
--- a/loader/loader.h
+++ b/loader/loader.h
@@ -302,7 +302,7 @@
         VkPhysicalDevice                        physicalDevice,
         VkFormat                                format,
         VkImageType                             type,
-        uint32_t                                samples,
+        VkSampleCountFlagBits                   samples,
         VkImageUsageFlags                       usage,
         VkImageTiling                           tiling,
         uint32_t*                               pNumProperties,