simtrace2_api: Fix transmission of SIMTRACE_CMD_BD_BOARD_INFO

Prior to this commit we didn't pass the pointer to the slot when
requesting board_info.

Change-Id: Ib99e7c0a96f7738480ca68ed2c144c1756a5f11b
diff --git a/host/lib/simtrace2_api.c b/host/lib/simtrace2_api.c
index c3c61a4..eeacb36 100644
--- a/host/lib/simtrace2_api.c
+++ b/host/lib/simtrace2_api.c
@@ -163,7 +163,7 @@
 {
 	struct msgb *msg = st_msgb_alloc();
 
-	return osmo_st2_slot_tx_msg(0, msg, SIMTRACE_MSGC_GENERIC, SIMTRACE_CMD_BD_BOARD_INFO);
+	return osmo_st2_slot_tx_msg(slot, msg, SIMTRACE_MSGC_GENERIC, SIMTRACE_CMD_BD_BOARD_INFO);
 }