[Fontations-backend] rustfmt ffi.rs

Run formatter on ffi.rs

Change-Id: I617c90a5be2ce9314c3bc05cfa75bebdd6b0f9ce
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/825557
Reviewed-by: Julia Lavrova <jlavrova@google.com>
Reviewed-by: Dominik Röttsches <drott@google.com>
Commit-Queue: Dominik Röttsches <drott@google.com>
1 file changed