Merge changes from topic "gralloc-drm_hwc-prep"

* changes:
  hikey960: gralloc960: Tweak allocation so every HWC allocation doesn't come out of cma
  hikey960: gralloc960: Add support for building w/  drm_hwcomposer
  hikey960: gralloc960: Add usage field to map to older code
  hikey: gralloc: Allow use of CMA heap instead of fbdev
  hikey: gralloc: Add union alias and additional fields to improve interop w/ hikey960 gralloc
  hikey: gralloc: Change to allow gralloc_priv.h to be shared
  gralloc/gralloc960: Drop linux/ion.h references as its gone