[rtcp] Pli::Parse updated not to use RTCPUtility

BUG=webrtc:5260
R=åsapersson

Review URL: https://codereview.webrtc.org/1811933002

Cr-Original-Commit-Position: refs/heads/master@{#12104}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: f752f85f3dc3b0306262a7d77466059107f4dc84
3 files changed