Remove TODO in ffmpeg extension README.md.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=139453745

extensions/ffmpeg/README.md

@@ -31,7 +31,7 @@ FFMPEG_EXT_PATH="${EXOPLAYER_ROOT}/extensions/ffmpeg/src/main"
 NDK_PATH="<path to Android NDK>"
 ```
 
-* Fetch and build ffmpeg.
+* Fetch and build FFmpeg.
 
 For example, to fetch and build for armv7a:
 
@@ -75,7 +75,7 @@ cd "${FFMPEG_EXT_PATH}"/jni && \
 ${NDK_PATH}/ndk-build APP_ABI=armeabi-v7a -j4
 ```
 
-TODO: Add instructions for other ABIs.
+Repeat these steps for any other architectures you need to support.
 
 * In your project, you can add a dependency on the extension by using a rule
   like this: