nuplayer: Always copy duration to output format message

 * In the case of PCM offload, we need to make sure the format is copied
   because we might not have it here.

Change-Id: Icd4ae5ceff66b24e83fe6a2b9a07ec8934590678
Merge branch 'cm-12.0' of https://github.com/CyanogenMod/android_frameworks_av into mkl