[mediacodec] Match new and delete.

Test run in build with "--variant=asan/codec_runner_sw_ffmpeg_tests"

MTWN-222 #done

TEST: fx run-test codec_runner_sw_ffmpeg_tests
Change-Id: If19086064475fe4afea909fc7fb42a220cc5c254
diff --git a/bin/media/codecs/sw/ffmpeg/mpsc_queue.h b/bin/media/codecs/sw/ffmpeg/mpsc_queue.h
index 657a9f4..816a84b 100644
--- a/bin/media/codecs/sw/ffmpeg/mpsc_queue.h
+++ b/bin/media/codecs/sw/ffmpeg/mpsc_queue.h
@@ -51,9 +51,9 @@
     }
 
     T elem = std::move(cache_->element);
-    Cell* to_free = cache_;
+    Cell* to_delete = cache_;
     cache_ = cache_->next;
-    free(to_free);
+    delete to_delete;
     return elem;
   }