Use new stat item/ctr getter APIs

Generated with spatch:
"""
@@
expression E1, E2;
@@
- &E2->ctr[E1]
+ rate_ctr_group_get_ctr(E2, E1)
"""

"""
@@
expression E1, E2, E3;
@@
- E2->items[E1]
+ osmo_stat_item_group_get_item(E2, E1)
"""

Change-Id: I41297a8df68e28dfc6016330ac82b0ed5dd0ebc1
diff --git a/src/gb/gprs_ns2.c b/src/gb/gprs_ns2.c
index 1148d6f..d72f34e 100644
--- a/src/gb/gprs_ns2.c
+++ b/src/gb/gprs_ns2.c
@@ -1255,8 +1255,8 @@
 	log_set_context(LOG_CTX_GB_NSE, nsvc->nse);
 	log_set_context(LOG_CTX_GB_NSVC, nsvc);
 
-	rate_ctr_inc(&nsvc->ctrg->ctr[NS_CTR_PKTS_IN]);
-	rate_ctr_add(&nsvc->ctrg->ctr[NS_CTR_BYTES_IN], msg->len);
+	rate_ctr_inc(rate_ctr_group_get_ctr(nsvc->ctrg, NS_CTR_PKTS_IN));
+	rate_ctr_add(rate_ctr_group_get_ctr(nsvc->ctrg, NS_CTR_BYTES_IN), msg->len);
 
 	if (msg->len < sizeof(struct gprs_ns_hdr)) {
 		rc = -EINVAL;