refactor(plat/st): updates for OP-TEE

Protect BL32 (SP_min) with MMU if OP-TEE is not used.
Validate OP-TEE header with optee_header_is_valid().
Use default values in bl2_mem_params_descs[]. They will be overwritten
in bl2_plat_handle_post_image_load() if OP-TEE is used.

Change-Id: I8614f3a17caa827561614d0f25f30ee90c4ec3fe
Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
2 files changed