chore: update NOTICE (#449)

- Updates the `NOTICE` to reflect Broadcom.
- Updates the filename to match our standard of `NOTICE`.

Signed-off-by: Ryan Johnson <ryan.johnson@broadcom.com>

Author: tenthirtyam

NOTICE

@@ -1,8 +1,7 @@
-Terraform Provider for Tanzu Mission Control
+// © Broadcom. All Rights Reserved.
+// The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries.
+// SPDX-License-Identifier: MPL-2.0
 
-Copyright 2021 VMware, Inc.
-
-This product is licensed to you under the Mozilla Public license, Version 2.0 (the "License").  You may not use this product except in compliance with the Mozilla Public License.  
-
-This product may include a number of subcomponents with separate copyright notices and license terms. Your use of these subcomponents is subject to the terms and conditions of the subcomponent's license, as noted in the LICENSE file. 
+This product is licensed to you under the Mozilla Public license, Version 2.0 (the "License").  You may not use this product except in compliance with the Mozilla Public License.
 
+This product may include a number of subcomponents with separate copyright notices and license terms. Your use of these subcomponents is subject to the terms and conditions of the subcomponent's license, as noted in the LICENSE file.