Add test case for booting from initrd and sd card.
Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Tested-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>