Revert "media_codecs: use ffmpeg for wma for now"

This partially reverts commit e51a1d6cd709c0bdeaae8d2553af4021cefaa5e5.

* This was fixed with http://review.cyanogenmod.org/#/c/74782/
  and http://review.cyanogenmod.org/#/c/74783/
* Leave FFMPEG WMA entry so we can fall back to software decoder
  in case the hardware decoder fails

Change-Id: I2c2f2022aa8713fa5628909fe2c451cdec270e8a