Resolve "ASAN in ISM to SBA conversion in JBM"

• Related issues: #678 (closed)
• Requested reviewers:

Reason why this change is needed

Clang asan santizier found an error in ivas_ism2sba_sf, the gain update might access the interpolator beyond its borders

Description of the change

Fix access to the interpolator

Affected operating points

• JBM ISM with decoding
• Produced bitstream is BE compared to previous state.

Related to #678 (closed)