drm/msm/dpu: enable DPU_SSPP_QOS_8LVL for SM8250

SM8250 platform has a 8-Levels VIG QoS setting. This setting was missed
due to bad interaction with b8dab65b ("drm/msm/dpu: Move
DPU_SSPP_QOS_8LVL bit to SDM845 and SC7180 masks"), which was applied in
parallel.

Fixes: d21fc5df ("drm/msm/dpu1: add support for qseed3lite used on sm8250")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>