Fix producer_fec_fuzzer.
Fix producer_fec_fuzzer.

A field was removed from FecProtectionParams in
https://codereview.webrtc.org/1917083003.

BUG=webrtc:5066
R=turaj@webrtc.org, turajs@webrtc.org

Review URL: https://codereview.webrtc.org/1922283002 .

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#12518}

TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc