These should be written as ChromeOS and ChromiumOS (without the space)
to match the updated branding. The copyright headers were already
migrated to the new style (https://crrev.com/c/3894243), but there were
some more instances left over.

BUG=None
TEST=tools/cargo-doc

Change-Id: I8c76aea2eb33b2e370ab71ee9b5cc0a4cfd00585
Reviewed-on: https://chromium-review.googlesource.com/c/crosvm/crosvm/+/4129934
Reviewed-by: Dennis Kempin <denniskempin@google.com>
Commit-Queue: Daniel Verkamp <dverkamp@chromium.org>