layers: Add debug report header

Enable output of a short message header containing definitions of
debug message types.

Change-Id: Ia84fb0e79d599b8d022b7d78267b7b6a0307823e
diff --git a/layers/VkLayer_utils.def b/layers/VkLayer_utils.def
index d2b5285..629c7d0 100644
--- a/layers/VkLayer_utils.def
+++ b/layers/VkLayer_utils.def
@@ -43,3 +43,5 @@
 layer_debug_actions
 util_GetExtensionProperties
 util_GetLayerProperties
+LogMessageInitialized
+SetLogMessageInitialized