nfp: fix variable dereferenced before check in nfp_app_ctrl_rx_raw()

'app' is dereferenced before used for the devlink trace point.
In case FW is buggy and sends a control message to a VF queue
we should make sure app is not NULL.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

drivers/net/ethernet/netronome/nfp/nfp_app.h

@@ -392,9 +392,10 @@ static inline void nfp_app_ctrl_rx(struct nfp_app *app, struct sk_buff *skb)
 static inline void
 nfp_app_ctrl_rx_raw(struct nfp_app *app, const void *data, unsigned int len)
 {
-	trace_devlink_hwmsg(priv_to_devlink(app->pf), true, 0, data, len);
+	if (!app || !app->type->ctrl_msg_rx_raw)
+		return;
 
-	if (app && app->type->ctrl_msg_rx_raw)
+	trace_devlink_hwmsg(priv_to_devlink(app->pf), true, 0, data, len);
 	app->type->ctrl_msg_rx_raw(app, data, len);
 }