Merge changes from topic "mp/exceptions" into integration

* changes:
  docs(ras): update RAS documentation
  docs(el3-runtime): update BL31 exception vector handling
  fix(el3-runtime): restrict lower el EA handlers in FFH mode
  fix(ras): remove RAS_FFH_SUPPORT and introduce FFH_SUPPORT
  fix(ras): restrict ENABLE_FEAT_RAS to have only two states
  feat(ras): use FEAT_IESB for error synchronization
  feat(el3-runtime): modify vector entry paths