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/loader/debug_report.c b/loader/debug_report.c
index 5ef5c49..4ee3a3c 100644
--- a/loader/debug_report.c
+++ b/loader/debug_report.c
@@ -43,7 +43,7 @@
 
 static const struct loader_extension_property debug_report_extension_info = {
     .info =  {
-        .extName = DEBUG_REPORT_EXTENSION_NAME,
+        .extName = VK_DEBUG_REPORT_EXTENSION_NAME,
         .specVersion = VK_DEBUG_REPORT_EXTENSION_VERSION,
         },
     .origin = VK_EXTENSION_ORIGIN_LOADER,
@@ -62,7 +62,7 @@
     ptr_instance->debug_report_enabled = false;
 
     for (uint32_t i = 0; i < pCreateInfo->extensionCount; i++) {
-        if (strcmp(pCreateInfo->ppEnabledExtensionNames[i], DEBUG_REPORT_EXTENSION_NAME) == 0) {
+        if (strcmp(pCreateInfo->ppEnabledExtensionNames[i], VK_DEBUG_REPORT_EXTENSION_NAME) == 0) {
             ptr_instance->debug_report_enabled = true;
             return;
         }