Adding an aq mode for 360 videos

Adding an aq mode for 360 videos

Different quality levels are used for different regions in
the frame depending on how far they are vertically from the
center. Specifically, three segments are used based on the
mi_row index with respect number to the number of mi_rows in
the frame.

Change-Id: Ifc8b777bc58ea8521dffc4640360c67d99f8d381