Revert "add chunk_alloc to playlist.c"
This reverts commit 89c021fbfa6cfad58d272769a1e8762cf32be204.
Reason for revert: crash when playing on disk playlist then playing a directory as an in-ram playlist
Change-Id: Ia5cf5da9f46f8c10c5c0f3707e7978c05664b8a4