According to the Chromium C++ style guide, there must be no `(c)` after
`Copyright`.

Bug: angleproject:5516
Change-Id: Id5b170b99a1aaf95ab7fabb35ed644b99b756ce1
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2690948
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Cody Northrop <cnorthrop@google.com>