VOL-2463 : Enable and disable pon/NNI port
changes in request_handler.go and iAdapter.go interface to accept request from core and process in voltha-openolt-adapter.

Change-Id: I9e4eb5da0a13d12997e95be3aadb0bd856792135
diff --git a/pkg/adapters/iAdapter.go b/pkg/adapters/iAdapter.go
index 3b86ac5..c0e44be 100644
--- a/pkg/adapters/iAdapter.go
+++ b/pkg/adapters/iAdapter.go
@@ -49,4 +49,6 @@
 	Cancel_image_download(device *voltha.Device, request *voltha.ImageDownload) (*voltha.ImageDownload, error)
 	Activate_image_update(device *voltha.Device, request *voltha.ImageDownload) (*voltha.ImageDownload, error)
 	Revert_image_update(device *voltha.Device, request *voltha.ImageDownload) (*voltha.ImageDownload, error)
+	Enable_port(deviceId string, port *voltha.Port) error
+	Disable_port(deviceId string, port *voltha.Port) error
 }