Merge branch 'refs/heads/t/wma_fixes'

The series also contains a fix for a silly bug which causes the decoder
to abort on empty output sizes, and a couple of cosmetic cleanups.

* refs/heads/t/wma_fixes (cooking for two weeks):
  wmadec: Remove two pointless variables.
  wmadec: Remove a pointless cast.
  wmadec: Set data size to 0 if nothing was decoded.
  wma: Fix packet size calculation.
  wmadec: Properly handle empty outputs.
  wma_common: Fix typo in log message.