igc: Add support for XDP_REDIRECT action

Add support for the XDP_REDIRECT action which enables XDP programs to
redirect packets arriving at I225 NIC. It also implements the
ndo_xdp_xmit ops, enabling the igc driver to transmit packets forwarded
to it by xdp programs running on other interfaces.

The patch tweaks the driver's page counting and recycling scheme as
described in the following two commits and implemented by other Intel
drivers in order to properly support XDP_REDIRECT action:
  commit 8ce29c67 ("i40e: tweak page counting for XDP_REDIRECT")
  commit 75aab4e1

 ("i40e: avoid premature Rx buffer reuse")

This patch has been tested with the sample apps "xdp_redirect_cpu" and
"xdp_redirect_map" located in samples/bpf/.

Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Signed-off-by: Vedang Patel <vedang.patel@intel.com>
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Dvora Fuxbrumer <dvorax.fuxbrumer@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>