warp7: include: configs: Differentiate bootscript address from loadaddr

Reusing the loadaddr to load the boot script breaks some of the logic we
want to have around the bootscript/FIT load addresses. Making a dedicated
bootscript address allows us to differentiate the bootscript load address
from the Linux Kernel or OPTEE load address, thus ensuring that no matter
what the load sequence the bootscript and Kernel/OPTEE binary load
addresses do not conflict.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>