drm/bridge: cdns-dsi: Update htotal in cdns_dsi_mode2cfg()

cdns_dsi_mode2cfg() calculates the dsi timings, but for some reason
doesn't set the htotal based on those timings. It is set only later, in
cdns_dsi_adjust_phy_config().

As cdns_dsi_mode2cfg() is the logical place to calculate it, let's move
it there. Especially as the following patch will remove
cdns_dsi_adjust_phy_config().

Reviewed-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
Tested-by: Parth Pancholi <parth.pancholi@toradex.com>
Tested-by: Jayesh Choudhary <j-choudhary@ti.com>
Reviewed-by: Devarsh Thakkar <devarsht@ti.com>
Link: https://lore.kernel.org/r/20250723-cdns-dsi-impro-v5-8-e61cc06074c2@ideasonboard.com
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

Author: tomba

drivers/gpu/drm/bridge/cadence/cdns-dsi-core.c

@@ -498,6 +498,13 @@ static int cdns_dsi_mode2cfg(struct cdns_dsi *dsi,
 	dsi_cfg->hfp = dpi_to_dsi_timing(mode->hsync_start - mode->hdisplay,
 					 bpp, DSI_HFP_FRAME_OVERHEAD);
 
+	dsi_cfg->htotal = dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
+	if (output->dev->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
+		dsi_cfg->htotal += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
+
+	dsi_cfg->htotal += dsi_cfg->hact;
+	dsi_cfg->htotal += dsi_cfg->hfp + DSI_HFP_FRAME_OVERHEAD;
+
 	return 0;
 }
 
@@ -514,12 +521,7 @@ static int cdns_dsi_adjust_phy_config(struct cdns_dsi *dsi,
 	unsigned int dsi_hfp_ext;
 	unsigned int lanes = output->dev->lanes;
 
-	dsi_htotal = dsi_cfg->hbp + DSI_HBP_FRAME_OVERHEAD;
-	if (output->dev->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)
-		dsi_htotal += dsi_cfg->hsa + DSI_HSA_FRAME_OVERHEAD;
-
-	dsi_htotal += dsi_cfg->hact;
-	dsi_htotal += dsi_cfg->hfp + DSI_HFP_FRAME_OVERHEAD;
+	dsi_htotal = dsi_cfg->htotal;
 
 	/*
 	 * Make sure DSI htotal is aligned on a lane boundary when calculating