netfilter: nf_dup_netdev: add nf_dev_xmit_recursion*() helpers and use them

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_dup_netdev: add nf_dev_xmit_recursion*() helpers and use them Update nft_dup and nft_fwd to use the nf_dev_xmit_recursion() helpers. This patch also disables BH when transmitting the skb to address a possible migration to different CPU leading to imbalanced decrementation of the recursion counters. This is modeled after Florian Westphal's dev_xmit_recursion*() API available since commit 97cdcf37b57e ("net: place xmit recursion in softnet data") according to its current state in the tree.