i40e: report BPF prog id during XDP_QUERY_PROG

Fill the XDP prog_id with the id just like we do in other XDP enabled
drivers such as ixgbe. This is needed so that on dump we can retrieve
the attached program based on the id, and dump BPF insns, opcodes, etc
back to user space. Only XDP driver missing this is currently i40e.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e_main.c

@@ -9601,6 +9601,7 @@ static int i40e_xdp(struct net_device *dev,
 		return i40e_xdp_setup(vsi, xdp->prog);
 	case XDP_QUERY_PROG:
 		xdp->prog_attached = i40e_enabled_xdp_vsi(vsi);
+		xdp->prog_id = vsi->xdp_prog ? vsi->xdp_prog->aux->id : 0;
 		return 0;
 	default:
 		return -EINVAL;