binman: btool: futility: use Bintool.version

Bintool.version can now be passed the binary argument to return the
version text, so there's no need to override it in futility anymore.

Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
1 file changed