xfrm: bring back device check in validate_xmit_xfrm

This is partial revert of commit d53dda2.

This change causes traffic using GSO with SW crypto running through a
NIC capable of HW offload to no longer get segmented during
validate_xmit_xfrm, and is unrelated to the bonding use case mentioned
in the commit.

Fixes: d53dda2 ("xfrm: Remove unneeded device check from validate_xmit_xfrm")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

Author: qsn

net/xfrm/xfrm_device.c

@@ -155,7 +155,8 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur
 		return skb;
 	}
 
-	if (skb_is_gso(skb) && unlikely(xmit_xfrm_check_overflow(skb))) {
+	if (skb_is_gso(skb) && (unlikely(x->xso.dev != dev) ||
+				unlikely(xmit_xfrm_check_overflow(skb)))) {
 		struct sk_buff *segs;
 
 		/* Packet got rerouted, fixup features and segment it. */