Addition of HW Revision to Wifi metrics

BUG:112541087
Change-Id: If71584373f2a62c7c915c3dec3777d02878b7fda
Merged-In: If71584373f2a62c7c915c3dec3777d02878b7fda
(cherry picked from commit 2e068a3bec55f9c192580fef5e55b992e1481d3b)
diff --git a/proto/src/wifi.proto b/proto/src/wifi.proto
index a98996d..b29c992 100644
--- a/proto/src/wifi.proto
+++ b/proto/src/wifi.proto
@@ -459,6 +459,9 @@
 
   // Histogram of the EAP method type of all installed Passpoint profiles
   repeated PasspointProfileTypeCount installed_passpoint_profile_type = 123;
+
+  // Hardware revision (EVT, DVT, PVT etc.)
+  optional string hardware_revision = 124;
 }
 
 // Information that gets logged for every WiFi connection.