style: remove redundant judgment

Signed-off-by: cndoit18 <cndoit18@outlook.com>

pkg/controller/replicaset/metrics/metrics.go

@@ -36,9 +36,5 @@ var SortingDeletionAgeRatio = metrics.NewHistogram(
 
 // Register registers ReplicaSet controller metrics.
 func Register(registrationFunc func(metrics.Registerable) error) error {
-	err := registrationFunc(SortingDeletionAgeRatio)
-	if err != nil {
-		return err
-	}
-	return nil
+	return registrationFunc(SortingDeletionAgeRatio)
 }