Revert "stagefright: Handle offload fallback for 24-bit tracks"

This reverts commit a1a9fb103219ec35a4b38246327436fe2ca8f3af.
Revert "stagefright: 24-bit audio support via offloading"

This reverts commit 53332b4e92d033e1c78529d45ed7f57702b17c88.