tflite: log: Fix vlog level parsing

The pointers should point to the stored strings, instead of the
temporary copied values.

BUG=b:305999697,b:340207771
TEST=bazel run --config=host_clang '//common:log_test'

Change-Id: Ied8b3080af535328eb7b3250fe998344abcc8469
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/tflite/+/5535489
Tested-by: Shik Chen <shik@chromium.org>
Commit-Queue: Shik Chen <shik@chromium.org>
Reviewed-by: Yi Chou <yich@google.com>

common/log.cc

diff --git a/common/log.cc b/common/log.cc
index e8ad441..159be56 100644
--- a/common/log.cc
+++ b/common/log.cc
@@ -76,7 +76,7 @@
   // Flags::Parse() will try to remove the parsed arguments from argv.
   int argc = args.size();
   std::vector<const char*> argv;
-  for (auto arg : args) {
+  for (const auto& arg : args) {
     argv.push_back(arg.data());
   }
   Flags::Parse(&argc, argv.data(), flags);