ubi: Mark expected switch fall-throughs

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Addresses-Coverity-ID: 1373884 ("Missing break in switch")
Addresses-Coverity-ID: 114869 ("Missing break in switch")
Addresses-Coverity-ID: 114870 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
index 93ceea4..e294d39 100644
--- a/drivers/mtd/ubi/attach.c
+++ b/drivers/mtd/ubi/attach.c
@@ -1072,6 +1072,7 @@ static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai,
 			 * be a result of power cut during erasure.
 			 */
 			ai->maybe_bad_peb_count += 1;
+		/* fall through */
 	case UBI_IO_BAD_HDR:
 			/*
 			 * If we're facing a bad VID header we have to drop *all*