Basop 2023 cleanup

• Related issues: #2023 (closed)
• Related float MR: ivas-codec-pc/ivas-codec!2604 (merged)
• Requested reviewers: @janssontoftg

Reason why this change is needed

• Small cleanup and one bug found in the implementation.

Description of the change

• Cleanup and simplification of the code under FIX_BASOP_2023_TDREND_DISTATT_PRECISION

Affected operating points

• TD renderer operation could be affected due to the bug. However, not triggered in any tests so far.