chore: update copyright and spdx

[tenthirtyam]

Summary of Pull Request

As discussed with Chip Childers:

• Updates or adds the Broadcom copyright, as needed.
• Updates or adds the SPDX-License-Identifier, as needed.
• Removes whitespace as noted.

Go:

// © Broadcom. All Rights Reserved.
// The term "Broadcom" refers to Broadcom Inc. and/or its subsidiaries.
// SPDX-License-Identifier: MPL-2.0

Type of Pull Request

• This is a bug fix.
• This is an enhancement or feature.
• This is a code style/formatting update.
• This is a documentation update.
• This is a refactoring update.
• This is a chore update
• This is something else.
  Please describe:

Related to Existing Issues

Test and Documentation Coverage

For bug fixes or features:

• Tests have been completed.
• Documentation has been added/updated.

Breaking Changes?

• Yes, there are breaking changes.
• No, there are no breaking changes.