drm/msm: Fix UBWC macrotile_mode for a680

Make it match the MDSS settings for sc8180x and downstream.

Note that without the previous commit that exposes the value of
macrotile_mode to mesa, this will break mesa which expects the legacy
default value of 0. Therefore we do *not* want to backport it.

Signed-off-by: Connor Abbott <cwabbott0@gmail.com>
Patchwork: https://patchwork.freedesktop.org/patch/607398/


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