Enable optimized meta path for libbnnmlowp

  - Detailed description of the meta path can be found here:
    https://github.com/google/gemmlowp/blob/master/meta/README
  - The optimized path give significant perf improvement.

Test: mm
Test: CTS BLAS tests pass
Test: On sailfish, performance measured by RsBlasBenchmark increased by
20+%

Change-Id: I3ea6af3d25ddc108cfbcf16874763b060ac0cae1
1 file changed