arm: pl310: Support processors without SCU
arm: pl310: Support processors without SCU

Not all processors might have a SCU unit. So conditionally include code
that configures SCU.

Signed-off-by: Akshay Bhat <124e9ed437bdfdc15bb6080f285761d3d4b394cb@timesys.com>
Acked-by: Jerome Forissier <ced78d268b4c9a0a20a59a9feeebd2ad90da03d3@linaro.org>

pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os,pascal-brand-st-dev/optee_os