Fixes: 46ddff2b ("qemu: boot from arm-tf")

Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Tested-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>