Multiple func definitions with TFLITE_SINGLE_ROUNDING
Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this [failed invocation](https://github.com/tensorflow/tensorflow/pull/62887/checks?check_run_id=21158191124) of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.
When TFLITE_SINGLE_ROUNDING is set, there are multiple function definitions for MultiplyByQuantizedMultiplier.

It's defined in `tensorflow/lite/kernels/internal/common.cc` and `tensorflow/lite/kernels/internal/common.h`. The problem lies in that `common.h` defines MultiplyByQuantizedMultiplier when TFLITE_SINGLE_ROUNDING is set, and `common.cc` defines it without a guard.

Change-Id: I3713ce80a56fe0ac115bde5d3d5eab3d6bc288ac