src: use namespace prefix osmo_fd* and osmo_select*

Summary of changes:

s/struct bsc_fd/struct osmo_fd/g
s/bsc_register_fd/osmo_fd_register/g
s/bsc_unregister_fd/osmo_fd_unregister/g
s/bsc_select_main/osmo_select_main/g
diff --git a/openbsc/src/utils/bs11_config.c b/openbsc/src/utils/bs11_config.c
index 8e987de..9cb6897 100644
--- a/openbsc/src/utils/bs11_config.c
+++ b/openbsc/src/utils/bs11_config.c
@@ -903,7 +903,7 @@
 	status_timer.cb = status_timer_cb;
 
 	while (1) {
-		bsc_select_main(0);
+		osmo_select_main(0);
 	}
 
 	abis_nm_bs11_factory_logon(g_bts, 0);