layers: Fix incorrect feature protect for KHX ext

Change-Id: I503c2984163455fd5fd91df6fa70da1dc88fc684
diff --git a/layers/object_tracker.cpp b/layers/object_tracker.cpp
index 9fbc1ad..74dac26 100644
--- a/layers/object_tracker.cpp
+++ b/layers/object_tracker.cpp
@@ -3403,11 +3403,11 @@
         if (strcmp(pCreateInfo->ppEnabledExtensionNames[i], VK_KHX_EXTERNAL_MEMORY_FD_EXTENSION_NAME) == 0) {
             device_data->enables.khx_external_memory_fd = true;
         }
-#ifdef VK_USE_PLATFORM_WIN32_KHR
+#ifdef VK_USE_PLATFORM_WIN32_KHX
         if (strcmp(pCreateInfo->ppEnabledExtensionNames[i], VK_KHX_EXTERNAL_MEMORY_WIN32_EXTENSION_NAME) == 0) {
             device_data->enables.khx_external_memory_win32 = true;
         }
-#endif  // VK_USE_PLATFORM_WIN32_KHR
+#endif  // VK_USE_PLATFORM_WIN32_KHX
         if (strcmp(pCreateInfo->ppEnabledExtensionNames[i], VK_KHX_EXTERNAL_SEMAPHORE_FD_EXTENSION_NAME) == 0) {
             device_data->enables.khx_external_semaphore_fd = true;
         }