Fix rate control issue with layers and aq-mode=3.

When aq-mode=3 is enabled, only for base layer frames should the
qp of the frame incorporate the segment delta-qp.

This was causing more rate mismatch for the enhancement layer frames
when running temporal layers with aq-mode=3 on.

Change-Id: I1c5e69d1ef8a51188af8696753c17fd8f67699b3
1 file changed