drm/msm/adreno: Move speedbin mapping to device table

This simplifies the code.

v2: Use a table of structs instead of flat uint32_t[]

Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/549769/