drm/msm/a6xx: Correct the highestbank configuration
Highest bank bit configuration is different for a618 gpu. Update
it with the correct configuration which is the reset value incidentally.
Signed-off-by: Akhil P Oommen <akhilpo@codeaurora.org> Signed-off-by: Sharat Masetty <smasetty@codeaurora.org> Fixes: e812744c5f95 ("drm: msm: a6xx: Add support for A618") Reviewed-by: Rob Clark <robdclark@gmail.com> Signed-off-by: Rob Clark <robdclark@chromium.org>