cactus: Don't remap memory regions at boot

This is not needed anymore. BSS, RODATA and RWDATA are defined in the
DTS file. SPM uses this information to map the corresponding memory
regions with the correct attributes so that the Secure Partition doesn't
have to do it.

Change-Id: I743b2ed2c7c9554b6af0d899a427515b1c943454
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>