Disable pin unlock for m53 only.

chrome/browser/chromeos/login/quick_unlock/pin_storage.cc

Index: chrome/browser/chromeos/login/quick_unlock/pin_storage.cc
diff --git a/chrome/browser/chromeos/login/quick_unlock/pin_storage.cc b/chrome/browser/chromeos/login/quick_unlock/pin_storage.cc
index 2030a63edbcbf1ca73329f6851edba77cc3d8882..312317bd30ca03355618f451f2e57cbb877fb884 100644
--- a/chrome/browser/chromeos/login/quick_unlock/pin_storage.cc
+++ b/chrome/browser/chromeos/login/quick_unlock/pin_storage.cc
@@ -104,8 +104,7 @@ std::string PinStorage::PinSecret() const {
 }
 
 bool PinStorage::IsPinAuthenticationAvailable() const {
-  return IsPinSet() && unlock_attempt_count() < kMaximumUnlockAttempts &&
-         HasStrongAuth() && TimeSinceLastStrongAuth() < kStrongAuthTimeout;
+  return false;
 }
 
 bool PinStorage::TryAuthenticatePin(const std::string& pin) {