JFFS2: add UBI support

This patch make JFFS2 able to work with UBI volumes via the emulated MTD
devices which are directly mapped to these volumes.

Signed-off-by: Artem Bityutskiy <dedekind@infradead.org>
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index abb90c0..8a649f6 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -672,6 +672,13 @@
 			return ret;
 	}
 
+	/* and an UBI volume */
+	if (jffs2_ubivol(c)) {
+		ret = jffs2_ubivol_setup(c);
+		if (ret)
+			return ret;
+	}
+
 	return ret;
 }
 
@@ -690,4 +697,9 @@
 	if (jffs2_nor_wbuf_flash(c)) {
 		jffs2_nor_wbuf_flash_cleanup(c);
 	}
+
+	/* and an UBI volume */
+	if (jffs2_ubivol(c)) {
+		jffs2_ubivol_cleanup(c);
+	}
 }