Merge changes from topic "ns/spmc_at_el3" into integration

* changes:
  feat(rdn2): add dts for secure partition
  feat(el3-spmc): synchronize access to the s-el0 sp context
  feat(el3-spmc): add support to map S-EL0 SP device regions
  feat(el3-spmc): add support to map S-EL0 SP memory regions
  feat(el3-spmc): add support for FFA_MEM_PERM_GET and SET ABIs
  feat(el3-spmc): add support to setup S-EL0 context