VOL-4270 fetching extended pm counters per uni

Change-Id: I2d1b1bbe39f0a49df7397853d00e3e05df987480
diff --git a/protos/voltha_protos/extensions.proto b/protos/voltha_protos/extensions.proto
index 61e9e45..81c7942 100755
--- a/protos/voltha_protos/extensions.proto
+++ b/protos/voltha_protos/extensions.proto
@@ -147,6 +147,10 @@
 
 message GetOmciEthernetFrameExtendedPmRequest {
     string onuDeviceId = 1;
+    oneof is_uni_index {
+        uint32 uniIndex = 2; // Index of the uni starting from 0
+    }
+    bool reset = 3;
 }
 
 message GetRxPowerRequest {