Implement the VK_KHR_swapchain_mutable_format device extension in the vulkan loader

Add an implementation for the VK_KHR_swapchain_mutable_format extension.

Test: Stepped through changes in debugger
Test: Ran sample app with VVL which used the extension
Test: Ran dEQP-VK.image.swapchain_mutable.android.* dEQP tests
Flag: com.android.graphics.libvulkan.flags.swapchain_mutable_format_ext
Bug: 341978292
Change-Id: Ib0e5b9f750cd5a94ab65419542898db207716fcc
diff --git a/vulkan/nulldrv/null_driver_gen.cpp b/vulkan/nulldrv/null_driver_gen.cpp
index d34851e..40a45af 100644
--- a/vulkan/nulldrv/null_driver_gen.cpp
+++ b/vulkan/nulldrv/null_driver_gen.cpp
@@ -24,6 +24,9 @@
 
 using namespace null_driver;
 
+/*
+ * This file is autogenerated by null_generator.py. Do not edit directly.
+ */
 namespace {
 
 struct NameProc {