Added script for setting up FVP and OP-TEE

The script will clone and download all needed Git's to run OP-TEE using
FVP (Foundation Models). The first time a user runs the script it will
acquire the needed software from various sources. This is followed by
configuring and building all needed components. In every sub-step there
will be a script created that could be used when building a component
later on.

There are some inter-dependencies between the software components. This
means that the developer using this setup must either now about the
inter-dependencies or if not sure, the developer could build everything
using two general helper scripts in the following order:
 1) build_secure.sh
 2) build_normal.sh

When a user needs to add new files to the root filesystem, he must
update the file "gen_rootfs/filelist-tee.txt".

Some developers might also have access to a Git containing tests
designed for testing OP-TEE functionality. In such case, the developer
can update the script so it matches the users login name (Linaro
account). If such access is granted there will also be tests built and
added by default when running this script.

Reviewed-by: Pascal Brand pascal.brand@linaro.org
Reviewed-by: Jens Wiklander jens.wiklander@linaro.org
"Dirty tests" renamed in "self tests"

Reviewed-by: Jens Wiklander jens.wiklander@linaro.org
Reviewed-by: Joakim Bech joakim.bech@linaro.org
Signed-off-by: Pascal Brand <pascal.brand@st.com>
Drivers gic and uart are optional

Platforms stm do not use gic and uart drivers, whereas vexpress (fvp / qemu)
does. So the conf.mk of the latter case defines the following:
    WITH_UART_DRV := y
    WITH_GIC_DRV := y

Reviewed-by: Joakim Bech joakim.bech@linaro.org
Reviewed-by: Jens Wiklander jens.wiklander@linaro.org
Signed-off-by: Pascal Brand <pascal.brand@st.com>