mlxsw: spectrum: Add traps needed for router implementation

mlxsw: spectrum: Add traps needed for router implementation

ip2me:
To instruct HW to send trapped ip2me traffic to kernel, we have to add
this trap. Selection ip2me traffic is introduced later on in this set.

ARPs:
We are going to stop flooding to CPU port when netdev isn't bridged and
only get packets destined to the netdev's IP address and certain control
packets.

Add traps for ARP request (broadcast) and response (unicast) in order to
get these to the CPU and resolve neighbours.

host miss:
If a packet is routed through a directly connected route and its
destination IP is not in the device's neighbour table, then we need to
trap it to CPU. This will cause the host to resolve the MAC of the
neighbour, which will be eventually programmed to the device's table.

router ingress:
In order to trap packets in router part.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>