mmc: sdhci-esdhc-imx: correct the max timeout count

i.MX USDHC Reference Manual has a mistake, for the register SYS_CTRL,
the DTOCV(bit 19~16) means the data timeout counter value. When DTOCV
is set to 0xF, it means SDCLK << 29, not SDCLK << 28.
Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
Acked-by: Dong Aisheng <aisheng.dong@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-esdhc-imx.c

@@ -929,7 +929,8 @@ static unsigned int esdhc_get_max_timeout_count(struct sdhci_host *host)
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
 
-	return esdhc_is_usdhc(imx_data) ? 1 << 28 : 1 << 27;
+	/* Doc Errata: the uSDHC actual maximum timeout count is 1 << 29 */
+	return esdhc_is_usdhc(imx_data) ? 1 << 29 : 1 << 27;
 }
 
 static void esdhc_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)