SMPP: remove duplicate g_smsc definition

The global g_smsc struct pointer is defined twice in the same file.
Let's keep the earlier definition.

Related: OS#5568
Change-Id: If96a44450563d45b707bdd4165cf3cf269db9906
diff --git a/src/libsmpputil/smpp_msc.c b/src/libsmpputil/smpp_msc.c
index 4a980ab..87cab00 100644
--- a/src/libsmpputil/smpp_msc.c
+++ b/src/libsmpputil/smpp_msc.c
@@ -793,8 +793,6 @@
 				deliver.sequence_number);
 }
 
-static struct smsc *g_smsc;
-
 bool smpp_route_smpp_first()
 {
 	return (bool)(g_smsc->smpp_first);