turnip: Put VK_KHR_external_fence_fd stubs back
tu_ImportFenceFdKHR is used by tu_AcquireImageANDROID, which may or may not work, but let's at least keep things compiling until somebody has time to tie up the loose ends on the Android side.
tu_ImportFenceFdKHR is used by tu_AcquireImageANDROID, which may or may not work, but let's at least keep things compiling until somebody has time to tie up the loose ends on the Android side.