message: Add cross build parameters to android build guide
diff: @@ -145,6 +145,7 @@ the root checkout directory as follows:
  ```sh
  bazel build -c opt --fat_apk_cpu=x86,x86_64,arm64-v8a,armeabi-v7a \
  + --host_crosstool_top=@bazel_tools//tools/cpp:toolchain \
  //tensorflow/lite/java:tensorflow-lite
  ```
  