bug 15045: vkGetPhysicalDeviceImageFormatProperties for unsupported formats (WIP)

Change the return type of vkGetPhysicalDeviceImageFormatProperties.

https://cvs.khronos.org/bugzilla/show_bug.cgi?id=15045
diff --git a/vulkan.py b/vulkan.py
index d7d7c2f..ed2f4a7 100755
--- a/vulkan.py
+++ b/vulkan.py
@@ -233,7 +233,7 @@
              Param("VkFormat", "format"),
              Param("VkFormatProperties*", "pFormatProperties")]),
 
-        Proto("void", "GetPhysicalDeviceImageFormatProperties",
+        Proto("VkResult", "GetPhysicalDeviceImageFormatProperties",
             [Param("VkPhysicalDevice", "physicalDevice"),
              Param("VkFormat", "format"),
              Param("VkImageType", "type"),