Notify Errors Appropriately from SoftMPEG2

This is to ensure that the framework realises that an error has
occured and does not call onQueueFilled if the error is fatal.

Bug: 36715268
Merged-In: If02499d306aa9b6df64a7f25d43d1bdf318a10cd
Change-Id: I6911d2e8899cc3a472b5ba5ecdcfbd92233ecfa6
(cherry picked from commit 7ae3111d2cb8bbdb3a73a90ab54ff43e44a0227a)