nuplayer: Avoid PCM offload when resampler is used

 * We don't support use of the resampler on the PCM offload path,
   this kind of defeats the purpose. While the offload output path
   handles most sample rates, there are cases such as Facebook's
   video preview which use weird formats like 24000KHz mono.
 * To resolve this in NuPlayer, compare metadata from the original
   format with the output format decided by the audio system. Fail
   offload if they don't match.

Change-Id: Ibf7c3a2fa4f54b56c39cc69b1ff6b474738ee339