net/mlx5e: Fix missing error assignment in mlx5e_xfrm_add_state()

Assign the return value of mlx5_eswitch_block_mode() to 'err' before
checking it to avoid returning an uninitialized error code.

Fixes: 22239eb ("net/mlx5e: Prevent tunnel reformat when tunnel mode not allowed")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202510271649.uwsIxD6O-lkp@intel.com/
Closes: http://lore.kernel.org/linux-rdma/aPIEK4rLB586FdDt@stanley.mountain/
Signed-off-by: Carolina Jubran <cjubran@nvidia.com>
Reviewed-by: Jianbo Liu <jianbol@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1762681073-1084058-2-git-send-email-tariqt@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: cjubran

drivers/net/ethernet/mellanox/mlx5/core/en_accel/ipsec.c

@@ -804,7 +804,8 @@ static int mlx5e_xfrm_add_state(struct net_device *dev,
 		goto err_xfrm;
 	}
 
-	if (mlx5_eswitch_block_mode(priv->mdev))
+	err = mlx5_eswitch_block_mode(priv->mdev);
+	if (err)
 		goto unblock_ipsec;
 
 	if (x->props.mode == XFRM_MODE_TUNNEL &&