mgcp_client: Use INET6_ADDRSTRLEN to store addresses in str format

Warning: This breaks libosmo-mgcp-cli ABI!

Related: SYS#4915
Change-Id: Ib778e9a72764103b52a462ea3c7fb56b23c1bcd6
diff --git a/src/libosmo-mgcp-client/mgcp_client.c b/src/libosmo-mgcp-client/mgcp_client.c
index b1909f0..146a59d 100644
--- a/src/libosmo-mgcp-client/mgcp_client.c
+++ b/src/libosmo-mgcp-client/mgcp_client.c
@@ -1121,7 +1121,7 @@
 {
 	unsigned int i;
 	int rc = 0;
-	char local_ip[INET_ADDRSTRLEN];
+	char local_ip[INET6_ADDRSTRLEN];
 	const char *codec;
 	unsigned int pt;