qed*: Support drop action classification

With this patch, User can configure for the supported
flows to be dropped. Added a stat "gft_filter_drop"
as well to be populated in ethtool for the dropped flows.

For example -

ethtool -N p5p1 flow-type udp4 dst-port 8000 action -1
ethtool -N p5p1 flow-type tcp4 scr-ip 192.168.8.1 action -1

Signed-off-by: Manish Chopra <manish.chopra@cavium.com>
Signed-off-by: Shahed Shaikh <shahed.shaikh@cavium.com>
Signed-off-by: Ariel Elior <ariel.elior@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>