sdhci: use SG_MITER_TO_SG/SG_MITER_FROM_SG

so the page will be flushed on unmap on ARCH which need it.
Signed-off-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>

drivers/mmc/host/sdhci.c

@@ -773,8 +773,14 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
 	}
 
 	if (!(host->flags & SDHCI_REQ_USE_DMA)) {
-		sg_miter_start(&host->sg_miter,
-			data->sg, data->sg_len, SG_MITER_ATOMIC);
+		int flags;
+
+		flags = SG_MITER_ATOMIC;
+		if (host->data->flags & MMC_DATA_READ)
+			flags |= SG_MITER_TO_SG;
+		else
+			flags |= SG_MITER_FROM_SG;
+		sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);
 		host->blocks = data->blocks;
 	}