Resolve "Bitrate mismatch in initial IGF configuration for some modes"

• Related issues: #920 (closed)
• Requested reviewers:

Reason why this change is needed

• Avoid triggering error message in IGF encoder config due to bitrate mismatch between functions getIgfPresent() and IGFEncSetMode() in initial IGF configuration.

Description of the change

• Give same bitrate to IGFEncSetMode() as was given to getIgfPresent().

Affected operating points

Does not affect bitstream or output.

Related to #920 (closed)