[SubmitActor] don't manually invalidate broken chains after linux 5.15

Fixes: 3fb3892b

emper/io/SubmitActor.cpp

@@ -72,7 +72,8 @@ void SubmitActor::receive(Future* future) {
 	// req1 -> invalid_req -> req3
 	// will submit only 2 instead of all 3 prepared sqes
 	// See: https://github.com/axboe/liburing/issues/186
-	if (unlikely(static_cast<unsigned>(submitted) < prepared)) {
+	if (unlikely(static_cast<unsigned>(submitted) < prepared) &&
+			emper::IO_MUST_INVALIDATE_BROKEN_CHAIN) {
 		io.cancelUnsubmittedChainParts<CallerEnvironment::EMPER>(*future);
 	}