migrate to osmo_fd_{read,write}_{enable,disable}()

Change-Id: I005826dfe3a8ad0fd6e08df2c87b38ce916bda2d
Depends: libosmocore.git Change-Id Idb89ba7bc7c129a6304a76900d17f47daf54d17d
diff --git a/src/trau/osmo_ortp.c b/src/trau/osmo_ortp.c
index 6e91f8d..d105ca8 100644
--- a/src/trau/osmo_ortp.c
+++ b/src/trau/osmo_ortp.c
@@ -218,7 +218,7 @@
 	if (what & OSMO_FD_READ) {
 		/* in polling mode, we don't want to be called here */
 		if (rs->flags & OSMO_RTP_F_POLL) {
-			fd->when &= ~OSMO_FD_READ;
+			osmo_fd_read_disable(fd);
 			return 0;
 		}
 		if (!recv_with_cb(rs))