rocker: implement rocker ofdpa flow table manipulation

The rocker driver maintains 4 hash tables: flows, groups, FDB, and VLANs.

Flow and group tables track the entries installed to OF-DPA tables,
per the OF-DPA spec.  See OF-DPA spec for full description of fields
in each flow and group table.  New table entries are pushed to the
device with ADD cmd.  Updated entries are pushed to the device with
MOD cmd.  For flow table entries, a crc32 key is made from fields of
the particular field.  For group table entries, the group_id is used
as the key.

The FDB table tracks fdb entries learned by the device or manually
pushed to the bridge by the user.  A crc32 key is made from the
port/mac/vlan tuple for the fdb entry.

The VLAN table tracks the ifindex-to-internal-vlan mapping for
untagged pkts.  On ingress, an untagged pkt is inserted with an
internal VLAN ID based on the input port's current internal VLAN ID.
The input port's internal VLAN will either be referenced by the port's
ifindex, if not bridged, or the containing bridge's ifindex, if
bridged.  Since the ifindex space isn't within a fixed range, uses a
hash table (with ifindex as key) to track internal VLAN ID for a given
ifindex.  The internal VLAN ID range is fixed and currently uses the
upper 255 VLAN IDs, starting at 0xf00.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>