mmc: fix comment typos

Correct spelling typo in drivers/mmc

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
index 322412c..eea9cf2 100644
--- a/drivers/mmc/host/atmel-mci.c
+++ b/drivers/mmc/host/atmel-mci.c
@@ -1021,7 +1021,7 @@
 }
 
 /*
- * Stop data transfer because error(s) occured.
+ * Stop data transfer because error(s) occurred.
  */
 static void atmci_stop_transfer_pdc(struct atmel_mci *host)
 {