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/handover_logic.c b/openbsc/src/libbsc/handover_logic.c
index 1aa8fde..0f1582e 100644
--- a/openbsc/src/libbsc/handover_logic.c
+++ b/openbsc/src/libbsc/handover_logic.c
@@ -96,7 +96,7 @@
 	DEBUGP(DHO, "(old_lchan on BTS %u, new BTS %u)\n",
 		old_lchan->ts->trx->bts->nr, bts->nr);
 
-	counter_inc(bts->network->stats.handover.attempted);
+	osmo_counter_inc(bts->network->stats.handover.attempted);
 
 	if (!old_lchan->conn) {
 		LOGP(DHO, LOGL_ERROR, "Old lchan lacks connection data.\n");
@@ -106,7 +106,7 @@
 	new_lchan = lchan_alloc(bts, old_lchan->type, 0);
 	if (!new_lchan) {
 		LOGP(DHO, LOGL_NOTICE, "No free channel\n");
-		counter_inc(bts->network->stats.handover.no_channel);
+		osmo_counter_inc(bts->network->stats.handover.no_channel);
 		return -ENOSPC;
 	}
 
@@ -182,7 +182,7 @@
 	struct gsm_network *net = ho->new_lchan->ts->trx->bts->network;
 
 	DEBUGP(DHO, "HO T3103 expired\n");
-	counter_inc(net->stats.handover.timeout);
+	osmo_counter_inc(net->stats.handover.timeout);
 
 	ho->new_lchan->conn->ho_lchan = NULL;
 	ho->new_lchan->conn = NULL;
@@ -262,7 +262,7 @@
 	     ho->old_lchan->ts->trx->bts->nr, new_lchan->ts->trx->bts->nr,
 	     ho->old_lchan->ts->trx->arfcn, new_lchan->ts->trx->arfcn);
 
-	counter_inc(net->stats.handover.completed);
+	osmo_counter_inc(net->stats.handover.completed);
 
 	osmo_timer_del(&ho->T3103);
 
@@ -300,7 +300,7 @@
 		return -ENODEV;
 	}
 
-	counter_inc(net->stats.handover.failed);
+	osmo_counter_inc(net->stats.handover.failed);
 
 	osmo_timer_del(&ho->T3103);
 	llist_del(&ho->list);