[VOL-5255] Use all uplink interfaces not only interface 0 at OLT

Raising new MR after addressing comments from the original MR.
Link to original MR:
https://gerrit.opencord.org/c/voltha-openolt-adapter/+/34993

Change-Id: Ic2b1589db87755ca62f656e18bc5e314c3e85cd8
Signed-off-by: Sridhar Ravindra <sridhar.ravindra@radisys.com>
diff --git a/internal/pkg/core/statsmanager.go b/internal/pkg/core/statsmanager.go
index 8cbc243..d978ee9 100644
--- a/internal/pkg/core/statsmanager.go
+++ b/internal/pkg/core/statsmanager.go
@@ -284,7 +284,8 @@
 	// Northbound and Southbound ports
 	// added to initialize the pm_metrics
 	var Ports interface{}
-	Ports, _ = InitPorts(ctx, "nni", Dev.device.Id, 1)
+	NumNniPorts := Dev.resourceMgr[0].DevInfo.GetNniPorts()
+	Ports, _ = InitPorts(ctx, "nni", Dev.device.Id, NumNniPorts)
 	StatMgr.NorthBoundPort, _ = Ports.(map[uint32]*NniPort)
 	NumPonPorts := Dev.resourceMgr[0].DevInfo.GetPonPorts()
 	Ports, _ = InitPorts(ctx, "pon", Dev.device.Id, NumPonPorts)