Resolve "stereo_dft_dec_reset() Mismatch between float and BASOP for resetting hStereoDft->res_gains_ind[][]"

• Related issues: #2560 (closed)
• Requested reviewers: @fotopoulou

Reason why this change is needed

• Bring BASOP code inline with float

Description of the change

• Align StereoDft->res_gains_ind_fx[][] with floating-point code

Affected operating points

• Change is BE.

Closes #2560 (closed)