VOL-4028: Update comments for laserBiasCurrent to clarify the units
conveyed by the adapter as milli-amphere instead of amphere.

Change-Id: Ic763d96989c0d7522f19bd840c7ac5b6cd5bf3c5
diff --git a/protos/voltha_protos/extensions.proto b/protos/voltha_protos/extensions.proto
index 7ea88c2..849934f 100644
--- a/protos/voltha_protos/extensions.proto
+++ b/protos/voltha_protos/extensions.proto
@@ -98,7 +98,7 @@
     float powerFeedVoltage = 1; // unit of value is voltage
     float receivedOpticalPower = 2; // unit of value is dBm
     float meanOpticalLaunchPower = 3; // unit of value is dBm
-    float laserBiasCurrent = 4; // unit of value is amphere
+    float laserBiasCurrent = 4; // unit of value is milli-amphere (mA)
     float temperature = 5; // unit of value is degree celsius
 }