Merge changes from topic "allwinner_mmap" into integration

* changes:
  refactor(plat/allwinner): clean up platform definitions
  refactor(plat/allwinner): do not map BL32 DRAM at EL3
  refactor(plat/allwinner): map SRAM as device memory by default
  refactor(plat/allwinner): rename static mmap region constant
  feat(bl_common): import BL_NOBITS_{BASE,END} when defined