Merge changes I31ec0001,Ib06cd024,I7c11f15d,Ie0d5d4c8,I285f3b59, ... into integration
* changes:
fix(el3-spmc): correctly account for emad_offset
refactor(el3-spmc): avoid unnecessarily revalidating offset
fix(el3-spmc): only call spmc_shm_check_obj() on complete objects
refactor(spmc): assert on out-of-bounds emad access
refactor(el3-spmc): spmc_shmem_obj_get_emad() will never fail
fix(el3-spmc): validate descriptor headers
fix(el3-spmc): use version-dependent minimum descriptor length
refactor(el3-spmc): check emad_count offset