Remove redundent GetObjectKind() defined on top-level types

TypeMeta is embedded in all these types and TypeMeta has GetObjectKind()
method to implement the runtime.Object interface.

plugin/pkg/scheduler/api/register.go

@@ -51,5 +51,3 @@ func addKnownTypes(scheme *runtime.Scheme) error {
 	)
 	return nil
 }
-
-func (obj *Policy) GetObjectKind() schema.ObjectKind { return &obj.TypeMeta }

plugin/pkg/scheduler/api/v1/register.go

@@ -54,5 +54,3 @@ func addKnownTypes(scheme *runtime.Scheme) error {
 	)
 	return nil
 }
-
-func (obj *Policy) GetObjectKind() schema.ObjectKind { return &obj.TypeMeta }