QEMU does not use flex/bison packages.

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Li-Wen Hsu <lwhsu@freebsd.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20200515163029.12917-5-philmd@redhat.com>