nfp: fix incorrect pointer deference when offloading IPsec with bonding

There are two pointers in struct xfrm_dev_offload, *dev, *real_dev.
The *dev points whether bonding interface or real interface, if
bonding IPsec offload is used, it points bonding interface; if not,
it points real interface. And *real_dev always points real interface.
So nfp should always use real_dev instead of dev.

Prior to this change the system becomes unresponsive when offloading
IPsec for a device which is a lower device to a bonding device.

Fixes: 859a497f ("nfp: implement xfrm callbacks and expose ipsec offload feature to upper layer")
CC: stable@vger.kernel.org
Signed-off-by: Huanhuan Wang <huanhuan.wang@corigine.com>
Acked-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Link: https://lore.kernel.org/r/20230420140125.38521-1-louis.peens@corigine.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/netronome/nfp/crypto/ipsec.c

@@ -269,7 +269,7 @@ static void set_sha2_512hmac(struct nfp_ipsec_cfg_add_sa *cfg, int *trunc_len)
 static int nfp_net_xfrm_add_state(struct xfrm_state *x,
 				  struct netlink_ext_ack *extack)
 {
-	struct net_device *netdev = x->xso.dev;
+	struct net_device *netdev = x->xso.real_dev;
 	struct nfp_ipsec_cfg_mssg msg = {};
 	int i, key_len, trunc_len, err = 0;
 	struct nfp_ipsec_cfg_add_sa *cfg;
@@ -513,7 +513,7 @@ static void nfp_net_xfrm_del_state(struct xfrm_state *x)
 		.cmd = NFP_IPSEC_CFG_MSSG_INV_SA,
 		.sa_idx = x->xso.offload_handle - 1,
 	};
-	struct net_device *netdev = x->xso.dev;
+	struct net_device *netdev = x->xso.real_dev;
 	struct nfp_net *nn;
 	int err;