[VOL-3774] Remove hardcording of NNI port speed

Change-Id: I1c1e50403ac0faabed31ed11be2b59a863c62cb9
diff --git a/agent/Makefile.in b/agent/Makefile.in
index 648c621..abcc0cc 100644
--- a/agent/Makefile.in
+++ b/agent/Makefile.in
@@ -48,7 +48,7 @@
 # This specifies the GIT tag in https://github.com/opencord/voltha-protos
 # repo that we need to refer to, to pick the right version of
 # openolt.proto and tech_profile.proto
-OPENOLT_PROTO_VER ?= v5.1.0
+OPENOLT_PROTO_VER ?= v5.2.1
 
 # Variables used for Inband build
 INBAND = "n"