mmc: dw_mmc: enable card read threshold when mode is HS400

Enable card-read-threshold, when eMMC mode is HS400.
Refer to f1d2736c (mmc: dw_mmc: control card read threshold)
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/dw_mmc.c

@@ -764,6 +764,7 @@ static void dw_mci_ctrl_rd_thld(struct dw_mci *host, struct mmc_data *data)
 		return;
 
 	if (host->timing != MMC_TIMING_MMC_HS200 &&
+	    host->timing != MMC_TIMING_MMC_HS400 &&
 	    host->timing != MMC_TIMING_UHS_SDR104)
 		goto disable;