GN: Build libvpx on ARM

My previous patch didn't work. Shouldn't use media_use_libvpx
because it's in third_party. Instead I just commented out the
entire target for NEON intrinsics.

TBR=tomfinegan@chromium.org

Review URL: https://codereview.chromium.org/547883002

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/libvpx@291844 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
1 file changed