[shortcut-fe] don't attempt to offload connection if net_device is shutting down

Change-Id: I74db33d05799736bb661c87e69074c88c7bbf2cb
Signed-off-by: Matthew McClintock <mmcclint@codeaurora.org>
diff --git a/shortcut-fe/sfe_ipv4.c b/shortcut-fe/sfe_ipv4.c
index 95776a8..d398329 100644
--- a/shortcut-fe/sfe_ipv4.c
+++ b/shortcut-fe/sfe_ipv4.c
@@ -2262,6 +2262,11 @@
 	dest_dev = sic->dest_dev;
 	src_dev = sic->src_dev;
 
+	if (unlikely((dest_dev->reg_state != NETREG_REGISTERED) ||
+		     (src_dev->reg_state != NETREG_REGISTERED))) {
+		return -EINVAL;
+	}
+
 	spin_lock_bh(&si->lock);
 	si->connection_create_requests++;