C2: Generate CSD in vp9 encoder

Bug: 342651775
Test: atest CtsMediaV2TestCases:CodecEncoderTest#testSimpleEncode
Test: atest MctsMediaV2TestCases:CodecEncoderTest#testSimpleEncode

Change-Id: I7d0cb30afd5f615238afc14324ebc08234007407
diff --git a/media/codec2/components/vpx/C2SoftVpxEnc.h b/media/codec2/components/vpx/C2SoftVpxEnc.h
index 980de04..87d24f9 100644
--- a/media/codec2/components/vpx/C2SoftVpxEnc.h
+++ b/media/codec2/components/vpx/C2SoftVpxEnc.h
@@ -207,6 +207,9 @@
      // Signalled EOS
      bool mSignalledOutputEos;
 
+     // Header generated
+     bool mHeaderGenerated;
+
      // Signalled Error
      bool mSignalledError;