Resolve "OSBA decoder crash with planar SBA input"

• Related issues: #926 (closed)
• Requested reviewers: @tyagiri , @bayers

Reason why this change is needed

Crash in OSBA decoder with planar FOA input

Description of the change

Fix calculation of number of JBM TCs in OSBA

Affected operating points

OSBA with planar FOA input is not BE (because the output is not produced without this fix) the bitstream is bitexact (decoder change only)

Related to #926 (closed)