A621 is a clear A662 derivative (same lineage as A650), no explosions
or sick features, other than a NoC bug which can stall the GPU..

Add support for it.
Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/611100/Signed-off-by: Rob Clark <robdclark@chromium.org>