drm/msm/dpu: Fix adjusted mode clock check for 3d merge

Since 3D merge allows for larger modes to be supported across 2 layer
mixers, filter modes based on adjusted mode clock / 2 when 3d merge is
supported.

Reported-by: Abel Vesa <abel.vesa@linaro.org>
Fixes: 62b7d68 ("drm/msm/dpu: Filter modes based on adjusted mode clock")
Signed-off-by: Jessica Zhang <jessica.zhang@oss.qualcomm.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Abel Vesa <abel.vesa@linaro.org>
Tested-by: Abel Vesa <abel.vesa@linaro.org>
Tested-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/676353/
Link: https://lore.kernel.org/r/20250923-modeclk-fix-v2-1-01fcd0b2465a@oss.qualcomm.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

Author: Jessica Zhang

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

@@ -1545,6 +1545,9 @@ static enum drm_mode_status dpu_crtc_mode_valid(struct drm_crtc *crtc,
 	adjusted_mode_clk = dpu_core_perf_adjusted_mode_clk(mode->clock,
 							    dpu_kms->perf.perf_cfg);
 
+	if (dpu_kms->catalog->caps->has_3d_merge)
+		adjusted_mode_clk /= 2;
+
 	/*
 	 * The given mode, adjusted for the perf clock factor, should not exceed
 	 * the max core clock rate