qlge: mark expected switch fall-through

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

Addresses-Coverity-ID: 114811 ("Missing break in switch")
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/qlogic/qlge/qlge_mpi.c

@@ -1176,6 +1176,7 @@ void ql_mpi_idc_work(struct work_struct *work)
 	case MB_CMD_PORT_RESET:
 	case MB_CMD_STOP_FW:
 		ql_link_off(qdev);
+		/* Fall through */
 	case MB_CMD_SET_PORT_CFG:
 		/* Signal the resulting link up AEN
 		 * that the frame routing and mac addr