[cleanup] fixed macros and includes in rtp_cvo.h
[cleanup] fixed macros and includes in rtp_cvo.h

assert macro replaced with RTC_NOTREACHED, added proper include for it.

R=asapersson@webrtc.org, åsapersson

Review URL: https://codereview.webrtc.org/1763973003 .

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#11886}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 96150a63224001c773bb62e7bba38ace02176827

Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,jchavanton/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,jchavanton/webrtc,jchavanton/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk