Changes for running FVP model from docker container

FVP model can be launched by executing ./run_docker.sh run_model -m model_path_in_container -d distro_opts
Change-Id: Ib86c7768afe5df328cdff42e24df23ea8f9e2969
Signed-off-by: Annam Sai Manisha <annam.saimanisha@arm.com>