[Non-BE] Resolve "JBM: SPAR low rate smoothing factor calculation may use undefined values"

• Related issues: #906 (closed)
• Requested reviewers: @tyagiri

Reason why this change is needed

The function ivas_spar_calc_smooth_facs() uses the constant MAX_PARAM_SPATIAL_SUBFRAMES to loop over the CLDFB time slots in a subframe. In the JBM case a subframe can have less CLDFB time slots than MAX_PARAM_SPATIAL_SUBFRAMES, so it will access undefined values in this case.

Description of the change

Fix said function to be aware of the correct subframe size.

Affected operating points

• SBA to HOA2 and HOA3 decoding and TSM active below 24.4 kbkps
• Produced bitstream is BE compared to previous state (no encoder change)

Related to #906 (closed)