vp9: Fix to the segment weight for cyclic refresh.
vp9: Fix to the segment weight for cyclic refresh.

For screen-content mode with aq-mode=3: use the proper
segment weight (remove division by 2).

Change-Id: I747575062c644df7ead3fa41525fb6d6bac04f4d

webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx