ixgbe: add tracking of AF_XDP zero-copy state for each queue pair

Here, we add a bitmap to the ixgbe_adapter that tracks if a
certain queue pair has been "zero-copy enabled" via the ndo_bpf.
The bitmap is used in ixgbe_xsk_umem, and enables zero-copy if
and only if XDP is enabled, the corresponding qid in the bitmap
is set, and the umem is non-NULL;

Signed-off-by: Jan Sokolowski <jan.sokolowski@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/ixgbe/ixgbe.h

@@ -635,6 +635,7 @@ struct ixgbe_adapter {
 	/* XDP */
 	int num_xdp_queues;
 	struct ixgbe_ring *xdp_ring[MAX_XDP_QUEUES];
+	unsigned long *af_xdp_zc_qps; /* tracks AF_XDP ZC enabled rings */
 
 	/* TX */
 	struct ixgbe_ring *tx_ring[MAX_TX_QUEUES] ____cacheline_aligned_in_smp;