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: efcd010 ("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

Author: lumag

drivers/gpu/drm/msm/disp/dpu1/catalog/dpu_9_0_sm8550.h

@@ -160,13 +160,15 @@ static const struct dpu_lm_cfg sm8550_lm[] = {
 		.sblk = &sdm845_lm_sblk,
 		.lm_pair = LM_3,
 		.pingpong = PINGPONG_2,
+		.dspp = DSPP_2,
 	}, {
 		.name = "lm_3", .id = LM_3,
 		.base = 0x47000, .len = 0x320,
 		.features = MIXER_SDM845_MASK,
 		.sblk = &sdm845_lm_sblk,
 		.lm_pair = LM_2,
 		.pingpong = PINGPONG_3,
+		.dspp = DSPP_3,
 	}, {
 		.name = "lm_4", .id = LM_4,
 		.base = 0x48000, .len = 0x320,