COMPMID-583 - Implemented reference implementation and validation tests (NEON and CL) for Histogram

Change-Id: Iccf6b4483cb8394dab2f861a737583126f9bed81
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/91601
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
8 files changed