ethtool: Add WAKE_FILTER and RX_CLS_FLOW_WAKE

Add the ability to specify through ethtool::rxnfc that a rule location is
special and will be used to participate in Wake-on-LAN, by e.g: having a
specific pattern be matched. When this is the case, fs->ring_cookie must
be set to the special value RX_CLS_FLOW_WAKE.

We also define an additional ethtool::wolinfo flag: WAKE_FILTER which
can be used to configure an Ethernet adapter to allow Wake-on-LAN using
previously programmed filters.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>