drm/msm/dpu: rearrange QoS setting code

Slightly rearrainge code in dpu_plane_sspp_update_pipe() to group
QoS/LUT related functions.

Reviewed-by: Jeykumar Sankaran <quic_jeykumar@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/537906/
Link: https://lore.kernel.org/r/20230518222238.3815293-5-dmitry.baryshkov@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>