Add HW Revision to Telecom Metrics

Test:
adb shell dumpsys telecomm
Hardware Version: EVT2.0

BUG:112541087
Change-Id: I108b7b43d6fbd9899b4adba51720f0dd9ef3980b
diff --git a/proto/telecom.proto b/proto/telecom.proto
index 9fd64db..df69ed7 100644
--- a/proto/telecom.proto
+++ b/proto/telecom.proto
@@ -13,6 +13,9 @@
 
   // Timing information for the logging sessions
   repeated LogSessionTiming session_timings = 2;
+
+  // Hardware revision (EVT, DVT, PVT etc.)
+  optional string hardware_revision = 3;
 }
 
 message LogSessionTiming {