xchange-93: Use VK_ prefix on DEBUG_REPORT_..._NAME

Use the Vulkan namespace (VK_ prefix) on DEBUG_REPORT_EXTENSION_NAME
This resolves LunarXchange bug #93.
https://vulkan.lunarg.com/app/issues/55b76ae37ef24d0001000070
diff --git a/layers/vk_layer_logging.h b/layers/vk_layer_logging.h
index f2952e9..b81a5e5 100644
--- a/layers/vk_layer_logging.h
+++ b/layers/vk_layer_logging.h
@@ -91,7 +91,7 @@
     memset(debug_data, 0, sizeof(debug_report_data));
     for (uint32_t i = 0; i < extension_count; i++) {
         /* TODO: Check other property fields */
-        if (strcmp(ppEnabledExtensions[i], DEBUG_REPORT_EXTENSION_NAME) == 0) {
+        if (strcmp(ppEnabledExtensions[i], VK_DEBUG_REPORT_EXTENSION_NAME) == 0) {
             debug_data->g_DEBUG_REPORT = true;
         }
     }