Keep TC channel pointers in one constant place during decoding and rendering

• Related issues: sa4/audio/ivas-basop#2396 (closed)
• Requested reviewers: @vaclav

Reason why this change is needed

See this comment

Description of the change

• Modified ivas_buffer_deinterleaved_to_interleaved and ivas_buffer_interleaved_to_deinterleaved so that they do not change the offset between consecutive channels in the deinterleaved buffer layout
• Removed code that adjusted channel pointers after they were modified by layout changes

Affected operating points

• All tests are BE