ntb: ntb_transport: Mark expected switch fall-throughs

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

Addresses-Coverity-ID: 1373888 ("Missing break in switch")
Addresses-Coverity-ID: 1373889 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Acked-by: Allen Hubbe <allenbh@gmail.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

drivers/ntb/ntb_transport.c

@@ -1278,6 +1278,7 @@ static void ntb_rx_copy_callback(void *data,
 		case DMA_TRANS_READ_FAILED:
 		case DMA_TRANS_WRITE_FAILED:
 			entry->errors++;
+			/* fall through */
 		case DMA_TRANS_ABORTED:
 		{
 			struct ntb_transport_qp *qp = entry->qp;
@@ -1533,6 +1534,7 @@ static void ntb_tx_copy_callback(void *data,
 		case DMA_TRANS_READ_FAILED:
 		case DMA_TRANS_WRITE_FAILED:
 			entry->errors++;
+			/* fall through */
 		case DMA_TRANS_ABORTED:
 		{
 			void __iomem *offset =