Remove unused texture format source files These files are not included in the build, they have been replaced by autogenerated files. TEST=build on Windows Change-Id: I6b8448d6f2426bc05c01b7ec6db605e6047ee207 Reviewed-on: https://chromium-review.googlesource.com/326660 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>