src: use namespace prefix osmo_counter*

Summary of changes:

s/struct counter/struct osmo_counter/g
s/counter_inc/osmo_counter_inc/g
s/counter_get/osmo_counter_get/g
s/counter_reset/osmo_counter_reset/g
s/counter_alloc/osmo_counter_alloc/g
s/counter_free/osmo_counter_free
diff --git a/openbsc/src/libbsc/gsm_04_08_utils.c b/openbsc/src/libbsc/gsm_04_08_utils.c
index 1cff1d9..7599cea 100644
--- a/openbsc/src/libbsc/gsm_04_08_utils.c
+++ b/openbsc/src/libbsc/gsm_04_08_utils.c
@@ -300,7 +300,7 @@
 		subscr = conn->subscr;
 	}
 
-	counter_inc(bts->network->stats.paging.completed);
+	osmo_counter_inc(bts->network->stats.paging.completed);
 
 	/* Stop paging on the bts we received the paging response */
 	paging_request_stop(conn->bts, subscr, conn, msg);