Merge changes from topic "st_mapping_update" into integration

* changes:
  feat(stm32mp1): enable BL2_IN_XIP_MEM to remove relocation sections
  refactor(stm32mp1): reduce MMU memory regions and split XLAT by context
  feat(st): map 2MB for ROM code
  fix(stm32mp1): restrict DEVICE2 mapping in BL2