stats: Set class_id in rate_ctr group descriptions

This commit adds the class_id initialiser to all rate_ctr_group_desc
definitions.

Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/gprs/gb_proxy.c b/openbsc/src/gprs/gb_proxy.c
index 5b3ee28..8cdf9a4 100644
--- a/openbsc/src/gprs/gb_proxy.c
+++ b/openbsc/src/gprs/gb_proxy.c
@@ -34,6 +34,7 @@
 #include <osmocom/core/talloc.h>
 #include <osmocom/core/select.h>
 #include <osmocom/core/rate_ctr.h>
+#include <osmocom/core/stats.h>
 
 #include <osmocom/gprs/gprs_ns.h>
 #include <osmocom/gprs/gprs_bssgp.h>
@@ -72,6 +73,7 @@
 	.group_description = "GBProxy Global Statistics",
 	.num_ctr = ARRAY_SIZE(global_ctr_description),
 	.ctr_desc = global_ctr_description,
+	.class_id = OSMO_STATS_CLASS_GLOBAL,
 };
 
 static int gbprox_relay2peer(struct msgb *old_msg, struct gbproxy_peer *peer,