mlxsw: spectrum: Convert matchall-based mirroring to new SPAN API

In matchall-based mirroring, mirroring is not done with ACLs, but a SPAN
agent is bound to the ingress / egress of a port and all incoming /
outgoing traffic is mirrored.

Convert this type of mirroring to use the new API.

First the SPAN agent is resolved, then the port is marked as analyzed
and its egress mirror buffer is potentially allocated. Lastly, the
binding is performed.

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