We're currently building everything except for this file.
Since 'fdt_create_empty_tree' can be useful for some
platforms, compile this one too.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Michael Zimmermann <sigmaepsilon92@gmail.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>