drm/msm/dpu: add layer mixer register dump to dpu snapshot

Add the missing layer mixer register dump information to
dpu snapshot to assist debugging.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Link: https://lore.kernel.org/r/1639621658-1500-1-git-send-email-quic_abhinavk@quicinc.com
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c

@@ -920,6 +920,11 @@ static void dpu_kms_mdp_snapshot(struct msm_disp_state *disp_state, struct msm_k
 		msm_disp_snapshot_add_block(disp_state, cat->sspp[i].len,
 				dpu_kms->mmio + cat->sspp[i].base, "sspp_%d", i);
 
+	/* dump LM sub-blocks HW regs info */
+	for (i = 0; i < cat->mixer_count; i++)
+		msm_disp_snapshot_add_block(disp_state, cat->mixer[i].len,
+				dpu_kms->mmio + cat->mixer[i].base, "lm_%d", i);
+
 	msm_disp_snapshot_add_block(disp_state, top->hw.length,
 			dpu_kms->mmio + top->hw.blk_off, "top");