adopt recent IPA related symbol rename
... which happened during recent migration of IPA functionality from
libosmo-abis into libosmocore.
diff --git a/openbsc/src/libbsc/bts_ipaccess_nanobts.c b/openbsc/src/libbsc/bts_ipaccess_nanobts.c
index c254127..fc7bf28 100644
--- a/openbsc/src/libbsc/bts_ipaccess_nanobts.c
+++ b/openbsc/src/libbsc/bts_ipaccess_nanobts.c
@@ -35,6 +35,7 @@
#include <openbsc/abis_rsl.h>
#include <openbsc/debug.h>
#include <osmocom/abis/subchan_demux.h>
+#include <osmocom/gsm/ipa.h>
#include <osmocom/abis/ipaccess.h>
#include <osmocom/core/logging.h>