[coreboot] Different Google copyright notices: »The Chromium OS Authors.« or Google, Inc.

[Paul Menzel]

Dear coreboot folks,

could you please unify the Google copyright notices.

For some time »The Chromium OS Authors.« was used. This exists also
without a space in »ChromiumOS« in the repository.

The latest commits seem to prefer »Google, Inc.«.

To avoid confusion, could this please be unified to the recommended one.

Thanks,

Paul