staging: lustre: ldlm: mark expected switch fall-through

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/ldlm/ldlm_request.c

@@ -1175,6 +1175,7 @@ ldlm_cancel_no_wait_policy(struct ldlm_namespace *ns, struct ldlm_lock *lock,
 	case LDLM_IBITS:
 		if (ns->ns_cancel && ns->ns_cancel(lock) != 0)
 			break;
+		/* fall through */
 	default:
 		result = LDLM_POLICY_SKIP_LOCK;
 		lock_res_and_lock(lock);