TFTF doesn't need to boot Secondary Cactus

Removed code that was booting Cactus Secondary, using FFA_RUN interface
from TFTF's SPM tests. Hafnium now boots all partitions according to
"boot-order" field value in the partition manifests.

Signed-off-by: J-Alves <joao.alves@arm.com>
Change-Id: I31a3507c92bffe81f78036da121259a5c19924cd
1 file changed