CCodec: reduce log amount for render warning

Bug: 124096926
Test: builds
Change-Id: I7fd7bd0da8e32793f87c0c8278c208d1b4d5bbb2
diff --git a/media/codec2/sfplugin/CCodecBufferChannel.h b/media/codec2/sfplugin/CCodecBufferChannel.h
index 1ea29b4..964121e 100644
--- a/media/codec2/sfplugin/CCodecBufferChannel.h
+++ b/media/codec2/sfplugin/CCodecBufferChannel.h
@@ -311,6 +311,7 @@
     Mutexed<ReorderStash> mReorderStash;
 
     std::atomic_bool mInputMetEos;
+    std::once_flag mRenderWarningFlag;
 
     inline bool hasCryptoOrDescrambler() {
         return mCrypto != nullptr || mDescrambler != nullptr;