C2SoftMpeg2Dec : Enable KEEP_THREADS_ACTIVE

Bug: 343793479
Test: atest MctsMediaV2TestCases
      atest MctsMediaDecoderTestCases
      atest MctsMediaCodecTestCases
      atest VtsHalMediaC2V1_0TargetVideoDecTest

Change-Id: I11eb3079281acb6a73ea9562b3e138373d9f8ebb
diff --git a/media/aconfig/swcodec_flags.aconfig b/media/aconfig/swcodec_flags.aconfig
index a435a43..9dd1fdd 100644
--- a/media/aconfig/swcodec_flags.aconfig
+++ b/media/aconfig/swcodec_flags.aconfig
@@ -12,3 +12,12 @@
   description: "Feature flag for APV Software C2 codec"
   bug: "376770121"
 }
+
+flag {
+  name: "mpeg2_keep_threads_active"
+  is_exported: true
+  is_fixed_read_only: true
+  namespace: "codec_fwk"
+  description: "Enable keep_threads_active in mpeg2 decoder"
+  bug: "343793479"
+}