igc: Fix NFC rules restoration

igc: Fix NFC rules restoration

When network interface is brought up, the driver re-enables the NFC
rules previously configured. However, this is done in reverse order
the rules were added and hardware filters are configured differently.

For example, consider the following rules:

$ ethtool -N eth0 flow-type ether dst 00:00:00:00:00:AA queue 0
$ ethtool -N eth0 flow-type ether dst 00:00:00:00:00:BB queue 1
$ ethtool -N eth0 flow-type ether dst 00:00:00:00:00:CC queue 2
$ ethtool -N eth0 flow-type ether dst 00:00:00:00:00:DD queue 3

RAL/RAH registers are configure so filter index 1 has address ending
with AA, filter index 2 has address ending in BB, and so on.

If we bring the interface down and up again, RAL/RAH registers are
configured so filter index 1 has address ending in DD, filter index 2
has CC, and so on. IOW, in reverse order we had before bringing the
interface down.

This issue can be fixed by traversing adapter->nfc_rule_list in
backwards when restoring the rules. Since hlist doesn't support
backwards traversal, this patch replaces it by list_head and fixes
igc_restore_nfc_rules() accordingly.

Signed-off-by: Andre Guedes <andre.guedes@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>