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-bsc_nat/bsc_nat_utils.c b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
index 4f90cdf..8765f27 100644
--- a/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
+++ b/openbsc/src/osmo-bsc_nat/bsc_nat_utils.c
@@ -95,12 +95,12 @@
 	INIT_LLIST_HEAD(&nat->access_lists);
 	INIT_LLIST_HEAD(&nat->dests);
 
-	nat->stats.sccp.conn = counter_alloc("nat.sccp.conn");
-	nat->stats.sccp.calls = counter_alloc("nat.sccp.calls");
-	nat->stats.bsc.reconn = counter_alloc("nat.bsc.conn");
-	nat->stats.bsc.auth_fail = counter_alloc("nat.bsc.auth_fail");
-	nat->stats.msc.reconn = counter_alloc("nat.msc.conn");
-	nat->stats.ussd.reconn = counter_alloc("nat.ussd.conn");
+	nat->stats.sccp.conn = osmo_counter_alloc("nat.sccp.conn");
+	nat->stats.sccp.calls = osmo_counter_alloc("nat.sccp.calls");
+	nat->stats.bsc.reconn = osmo_counter_alloc("nat.bsc.conn");
+	nat->stats.bsc.auth_fail = osmo_counter_alloc("nat.bsc.auth_fail");
+	nat->stats.msc.reconn = osmo_counter_alloc("nat.msc.conn");
+	nat->stats.ussd.reconn = osmo_counter_alloc("nat.ussd.conn");
 	nat->auth_timeout = 2;
 	nat->ping_timeout = 20;
 	nat->pong_timeout = 5;