drm/msm/dpu: link DSPP_2/_3 blocks on SM8550

Link DSPP_2 to the LM_2 and DSPP_3 to the LM_3 mixer blocks. This allows
using colour transformation matrix (aka night mode) with more outputs at
the same time.

Fixes: efcd0107 ("drm/msm/dpu: add support for SM8550")
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/629961/
Link: https://lore.kernel.org/r/20241220-dpu-fix-catalog-v2-6-38fa961ea992@linaro.org