Now that the coverage build has fully switched to the VFS sub-system these functions were no longer available, so add them to the uos_vfs module. Also, vfs_open is no longer needed, it's available as the built-in open.
Now that the coverage build has fully switched to the VFS sub-system these functions were no longer available, so add them to the uos_vfs module. Also, vfs_open is no longer needed, it's available as the built-in open.