bug 15004: Non-coherent memory, when is flush and invalidate required

Add nonCoherentAtomSize.

https://cvs.khronos.org/bugzilla/show_bug.cgi?id=15004
diff --git a/include/vulkan/vulkan.h b/include/vulkan/vulkan.h
index 15e89b5..4eb7e96 100644
--- a/include/vulkan/vulkan.h
+++ b/include/vulkan/vulkan.h
@@ -1288,6 +1288,7 @@
     VkBool32                                    standardSampleLocations;
     VkDeviceSize                                optimalBufferCopyOffsetAlignment;
     VkDeviceSize                                optimalBufferCopyRowPitchAlignment;
+    VkDeviceSize                                nonCoherentAtomSize;
 } VkPhysicalDeviceLimits;
 
 typedef struct VkPhysicalDeviceSparseProperties {