Widen suppressions for misunderstood atomics.

Signature changed with new roll.

BUG=239350
TEST=none
TBR=zhaoqin

Review URL: https://codereview.chromium.org/23626003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221815 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/tsan/suppressions.txt

@@ -1082,9 +1082,7 @@
   ThreadSanitizer:Race
   fun:av_buffer_unref
   fun:av_frame_unref
-  fun:avcodec_decode_video2
   ...
-  fun:media::FFmpegVideoDecoder::Decode
 }
 {
   bug_256792
@@ -1129,3 +1127,4 @@
   fun:content::UtilityThreadImpl::UtilityThreadImpl
   fun:content::UtilityMainThread::InitInternal
 }
+