ethdev: introduce generic filter control

ethdev: introduce generic filter control

Define a new API umbrella to configure any kind of Rx filtering.
New functions:
- rte_eth_dev_filter_supported
- rte_eth_dev_filter_ctrl

Filter types, operations, and structures are defined specifically in new
header file lib/librte_eth/rte_dev_ctrl.h.

As to the implementation discussion, please refer to
http://dpdk.org/ml/archives/dev/2014-September/005179.html

Signed-off-by: Jingjing Wu <jingjing.wu@intel.com>
Acked-by: Helin Zhang <helin.zhang@intel.com>
[Thomas: rename ops and remove unused types]
Acked-by: Thomas Monjalon <thomas.monjalon@6wind.com>