UBI: fix kernel-doc errors and warnings

No functional changes, just tweak comments to make kernel-doc
work fine and stop complaining.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/upd.c b/drivers/mtd/ubi/upd.c
index 3b8beb8..8b89cc1 100644
--- a/drivers/mtd/ubi/upd.c
+++ b/drivers/mtd/ubi/upd.c
@@ -268,6 +268,7 @@
 
 /**
  * ubi_more_update_data - write more update data.
+ * @ubi: UBI device description object
  * @vol: volume description object
  * @buf: write data (user-space memory buffer)
  * @count: how much bytes to write
@@ -385,6 +386,7 @@
 
 /**
  * ubi_more_leb_change_data - accept more data for atomic LEB change.
+ * @ubi: UBI device description object
  * @vol: volume description object
  * @buf: write data (user-space memory buffer)
  * @count: how much bytes to write