drm/msm/adreno: Add A635 speedbin 0xac (A643)

Downstream calls this the "speedbin 1", but that number is already
occupied. Use index two.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/559607/


Signed-off-by: Rob Clark <robdclark@chromium.org>