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/osmo-nitb/bsc_hack.c b/openbsc/src/osmo-nitb/bsc_hack.c
index 8e987b2..5e60441 100644
--- a/openbsc/src/osmo-nitb/bsc_hack.c
+++ b/openbsc/src/osmo-nitb/bsc_hack.c
@@ -195,7 +195,7 @@
 }
 
 /* timer handling */
-static int _db_store_counter(struct counter *counter, void *data)
+static int _db_store_counter(struct osmo_counter *counter, void *data)
 {
 	return db_store_counter(counter);
 }
@@ -203,7 +203,7 @@
 static void db_sync_timer_cb(void *data)
 {
 	/* store counters to database and re-schedule */
-	counters_for_each(_db_store_counter, NULL);
+	osmo_counters_for_each(_db_store_counter, NULL);
 	osmo_timer_schedule(&db_sync_timer, DB_SYNC_INTERVAL);
 }