Resolve "ivas_mdct_core_tns_ns_fx(): Calculation of subframe-length overly complex"

• Related issues: #2555 (closed)
• Requested reviewers: @tritthart

Reason why this change is needed

• Calculation of subframe-length overly complex using BASOP_Util_Divide3216_Scale();

Description of the change

• Replace by simple assignment or shr(X, 1).

Affected operating points

• All operating points are bit-exact.

Closes #2555 (closed)