tflite: script: Add license to generated accel.conf BUG=b:338910179, b:332423167 TEST=manual Change-Id: Iebc2f39e8a35f8a456724b864a44e535a47cb562 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/tflite/+/5981781 Tested-by: Ching-Kang Yen <chingkang@chromium.org> Reviewed-by: Tommy Chiang <ototot@google.com> Commit-Queue: Ching-Kang Yen <chingkang@chromium.org>