Fix for SEGV in ixheaacd_aacdec_decodeframe function.

For erroneous stream, coupling channel initialization memory
was overlapping with SBR scratch memory usage, causing unwanted
reset of the some of the pointers.
All initialization should take place in persistent memory.
As a fix, replaced scratch with persistent memory for initialization.

Bug:145264510
Test:poc in bug

Change-Id: Iaa757d0e87fd3a0b2f75c5288cfe662f556c871f
2 files changed