mmc: sdhci: add mmc structure for host

So that sdhci host would tell in the driver that the mmc current
attributes.

Signed-off-by: Lei Wen <leiwen@marvell.com>
diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index 4a92453..31c738e 100644
--- a/drivers/mmc/sdhci.c
+++ b/drivers/mmc/sdhci.c
@@ -377,6 +377,7 @@
 	}
 
 	mmc->priv = host;
+	host->mmc = mmc;
 
 	sprintf(mmc->name, "%s", host->name);
 	mmc->send_cmd = sdhci_send_command;