COMPMID-1727 - CL: Implement Gather

Change-Id: I3d859da09a4de1019bb8c2046725eab942247927
Reviewed-on: https://review.mlplatform.org/386
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Georgios Pinitas <georgios.pinitas@arm.com>
14 files changed