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/vulkan.py b/vulkan.py
index 7779f90..d7d7c2f 100755
--- a/vulkan.py
+++ b/vulkan.py
@@ -381,7 +381,7 @@
             [Param("VkPhysicalDevice", "physicalDevice"),
              Param("VkFormat", "format"),
              Param("VkImageType", "type"),
-             Param("uint32_t", "samples"),
+             Param("VkSampleCountFlagBits", "samples"),
              Param("VkImageUsageFlags", "usage"),
              Param("VkImageTiling", "tiling"),
              Param("uint32_t*", "pPropertyCount"),