sysmobts: Make the nanoBTS NM code work for the sysmobts

Use the is_ipaccess_bts method to check if this is either is
nanoBTS or sysmoBTS. The sysmobts type can now be used to bootstrap
a bts.
diff --git a/openbsc/src/libbsc/bts_ipaccess_nanobts.c b/openbsc/src/libbsc/bts_ipaccess_nanobts.c
index ebbd88d..b6616c0 100644
--- a/openbsc/src/libbsc/bts_ipaccess_nanobts.c
+++ b/openbsc/src/libbsc/bts_ipaccess_nanobts.c
@@ -276,7 +276,7 @@
 	struct gsm_bts_trx_ts *ts;
 	struct gsm_bts_gprs_nsvc *nsvc;
 
-	if (nsd->bts->type != GSM_BTS_TYPE_NANOBTS)
+	if (!is_ipaccess_bts(nsd->bts))
 		return 0;
 
 	/* This event-driven BTS setup is currently only required on nanoBTS */
@@ -396,7 +396,7 @@
 	if (!trx)
 		return -EINVAL;
 
-	if (trx->bts->type != GSM_BTS_TYPE_NANOBTS)
+	if (!is_ipaccess_bts(trx->bts))
 		return 0;
 
 	switch (foh->obj_class) {