Adding get rpc for edgecore adapter

Change-Id: Ic15ebe9b3d963bd9b8e721844f1ac4e3895711bc
diff --git a/voltha/adapters/asfvolt16_olt/protos/bal.proto b/voltha/adapters/asfvolt16_olt/protos/bal.proto
index 41fd78d..bcc92cb 100644
--- a/voltha/adapters/asfvolt16_olt/protos/bal.proto
+++ b/voltha/adapters/asfvolt16_olt/protos/bal.proto
@@ -77,4 +77,5 @@
      **/
     rpc BalCfgSet(BalCfg) returns(BalErr) {}
     rpc BalCfgClear(BalKey) returns(BalErr) {}
+    rpc BalCfgGet(BalKey) returns(BalCfg) {}
 }