vulkan: Add function stub & plumbing for KHR_swapchain_front_buffered

Test: build
Change-Id: I6ea2e33e708067f11069bda19c4b5ea167158913
diff --git a/vulkan/libvulkan/code-generator.tmpl b/vulkan/libvulkan/code-generator.tmpl
index 33c5719..9021972 100644
--- a/vulkan/libvulkan/code-generator.tmpl
+++ b/vulkan/libvulkan/code-generator.tmpl
@@ -705,6 +705,7 @@
 VK_KHR_surface
 VK_KHR_swapchain
 VK_GOOGLE_display_timing
+VK_KHR_swapchain_front_buffered
 {{end}}