Make .gni files always use LF endings.
Make .gni files always use LF endings.

This saves a lot of spam about dirty git formatting when changing
.gni files.

Bug: angleproject:3139
Change-Id: I244d5254ac6bd7bd1a7bedac5c34bd141fe0b9c0
Reviewed-on: https://chromium-review.googlesource.com/c/1460611
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Reviewed-by: Shahbaz Youssefi <582eeec4f08a2ccd61e3ef52115e6e7c571582de@chromium.org>
Commit-Queue: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle