The current implementation was done under the assumption that
the scan would cover 3 rows and 4 columns. The final adopted
design uses 3 rows and 3 columns. The current implementation
effectively scans the 3rd column twice. This commit removes this
repeated scan over the third column.

BUG=aomedia:1713

Change-Id: Ifc20424f126eacd1f76b9c21be5dba339adba10f