mmc: mediatek: Fixed bug where clock frequency could be set wrong

This patch can fix two issues:

Issue 1:
In previous code, div may be overflow when setting clock frequency
as f_min. We can use DIV_ROUND_UP to fix this boundary related
issue.

Issue 2:
In previous code, we can not set the correct clock frequency when
div equals 0xff.
Signed-off-by: Yong Mao <yong.mao@mediatek.com>
Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
Reviewed-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mtk-sd.c

@@ -580,7 +580,7 @@ static void msdc_set_mclk(struct msdc_host *host, unsigned char timing, u32 hz)
 		}
 	}
 	sdr_set_field(host->base + MSDC_CFG, MSDC_CFG_CKMOD | MSDC_CFG_CKDIV,
-			(mode << 8) | (div % 0xff));
+		      (mode << 8) | div);
 	sdr_set_bits(host->base + MSDC_CFG, MSDC_CFG_CKPDN);
 	while (!(readl(host->base + MSDC_CFG) & MSDC_CFG_CKSTB))
 		cpu_relax();
@@ -1559,7 +1559,7 @@ static int msdc_drv_probe(struct platform_device *pdev)
 	host->src_clk_freq = clk_get_rate(host->src_clk);
 	/* Set host parameters to mmc */
 	mmc->ops = &mt_msdc_ops;
-	mmc->f_min = host->src_clk_freq / (4 * 255);
+	mmc->f_min = DIV_ROUND_UP(host->src_clk_freq, 4 * 255);
 
 	mmc->caps |= MMC_CAP_ERASE | MMC_CAP_CMD23;
 	/* MMC core transfer sizes tunable parameters */