trxcon/l1sched: make l1sched_lchan_emit_data_cnf() NULL-safe

Passing NULL to l1sched_lchan_emit_data_cnf() is not normal and
generally not expected, but definitely not fatal enough to abort
the process completely (due to assertion failure).

Change-Id: Ie64c176265f66a6c1515c66eb465d7e60f6768db
---
M src/host/trxcon/src/sched_prim.c
1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/host/trxcon/src/sched_prim.c b/src/host/trxcon/src/sched_prim.c
index 67be75e..4974557 100644
--- a/src/host/trxcon/src/sched_prim.c
+++ b/src/host/trxcon/src/sched_prim.c
@@ -337,7 +337,8 @@
 {
 	struct l1sched_prim *prim;
 
-	OSMO_ASSERT(msg != NULL);
+	if (msg == NULL)
+		return -ENODEV;
 
 	/* convert from DATA.req to DATA.cnf */
 	prim = l1sched_prim_from_msgb(msg);

