net: Prepare gro for packet consuming gro callbacks

The upcomming IPsec ESP gro callbacks will consume the skb,
so prepare for that.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

net/xfrm/Kconfig

@@ -5,6 +5,10 @@ config XFRM
        bool
        depends on NET
 
+config XFRM_OFFLOAD
+       bool
+       depends on XFRM
+
 config XFRM_ALGO
 	tristate
 	select XFRM