Merge changes from topic "st_fip_fconf" into integration

* changes:
  feat(io_mtd): offset management for FIP usage
  feat(nand): count bad blocks before a given offset
  feat(plat/st): add helper to save boot interface
  fix(plat/st): improve DDR get size function
  refactor(plat/st): map DDR secure at boot
  refactor(plat/st): rework TZC400 configuration