UBI: use vmalloc for large buffers

UBI allocates temporary buffers of PEB size, which may be 256KiB.
Use vmalloc instead of kmalloc for such big temporary buffers.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 555d594..054a88d 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -650,7 +650,7 @@
 	uif_close(ubi);
 	ubi_eba_close(ubi);
 	ubi_wl_close(ubi);
-	kfree(ubi->vtbl);
+	vfree(ubi->vtbl);
 	put_mtd_device(ubi->mtd);
 	kfree(ubi_devices[ubi_num]);
 	ubi_devices[ubi_num] = NULL;