UBI: improve internal interfaces

Pass volume description object to the EBA function which makes
more sense, and EBA function do not have to find the volume
description object by volume ID.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

drivers/mtd/ubi/build.c

@@ -249,7 +249,7 @@ static void kill_volumes(struct ubi_device *ubi)
 
 	for (i = 0; i < ubi->vtbl_slots; i++)
 		if (ubi->volumes[i])
-			ubi_free_volume(ubi, i);
+			ubi_free_volume(ubi, ubi->volumes[i]);
 }
 
 /**
@@ -300,7 +300,7 @@ static int uif_init(struct ubi_device *ubi)
 
 	for (i = 0; i < ubi->vtbl_slots; i++)
 		if (ubi->volumes[i]) {
-			err = ubi_add_volume(ubi, i);
+			err = ubi_add_volume(ubi, ubi->volumes[i]);
 			if (err) {
 				ubi_err("cannot add volume %d", i);
 				goto out_volumes;