thermal: change WARNING level to EMERGENCY

Bug: 116540200
Test: VtsHalThermalV2_0TargetTest
Change-Id: I705da6145c37f94db457e33843e431675895880b
diff --git a/thermal/2.0/types.hal b/thermal/2.0/types.hal
index ad11849..a1c0325 100644
--- a/thermal/2.0/types.hal
+++ b/thermal/2.0/types.hal
@@ -71,9 +71,10 @@
     CRITICAL,
 
     /**
-     * User should be warned before shutdown.
+     * Key components in platform are shutting down due to thermal condition.
+     * Device functionalities will be limited.
      */
-    WARNING,
+    EMERGENCY,
 
     /**
      * Need shutdown immediately.