configs/validate: looser validation for RDT

Don't require CAT or MBA because we don't detect those correctly (we
don't support L2 or L3DATA/L3CODE for example, and in the future
possibly even more). With plain "ClosId mode" we don't really care: we
assign the container to a pre-configured CLOS without trying to do
anything smarter.

Moreover, this was a duplicate/redundant check anyway, as for CAT and
MBA there is another specific sanity check that is done if L3 or MB
is specified in the config.

libcontainer/configs/validate/validator.go

@@ -216,10 +216,6 @@ func sysctl(config *configs.Config) error {
 
 func intelrdtCheck(config *configs.Config) error {
 	if config.IntelRdt != nil {
-		if !intelrdt.IsCATEnabled() && !intelrdt.IsMBAEnabled() {
-			return errors.New("intelRdt is specified in config, but Intel RDT is not supported or enabled")
-		}
-
 		if config.IntelRdt.ClosID == "." || config.IntelRdt.ClosID == ".." || strings.Contains(config.IntelRdt.ClosID, "/") {
 			return fmt.Errorf("invalid intelRdt.ClosID %q", config.IntelRdt.ClosID)
 		}