Codec2 SimpleC2Component: Do not process any input after stop()

Bug: 322731059
Change-Id: Ia59a61e68e1bcc1e93f3ce24143f1e04a746f460
diff --git a/media/codec2/components/base/SimpleC2Component.cpp b/media/codec2/components/base/SimpleC2Component.cpp
index 06a21f6..aec6523 100644
--- a/media/codec2/components/base/SimpleC2Component.cpp
+++ b/media/codec2/components/base/SimpleC2Component.cpp
@@ -712,6 +712,7 @@
         case kWhatStop: {
             int32_t err = thiz->onStop();
             thiz->mOutputBlockPool.reset();
+            mRunning = false;
             Reply(msg, &err);
             break;
         }