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/utils/bs11_config.c b/openbsc/src/utils/bs11_config.c
index 9cb6897..6e82126 100644
--- a/openbsc/src/utils/bs11_config.c
+++ b/openbsc/src/utils/bs11_config.c
@@ -72,7 +72,7 @@
 static struct log_target *stderr_target;
 
 /* dummy function to keep gsm_data.c happy */
-struct counter *counter_alloc(const char *name)
+struct osmo_counter *osmo_counter_alloc(const char *name)
 {
 	return NULL;
 }