mlxsw: spectrum_span: Generalize SPAN support

To support mirroring to different device types, the functions that
partake in configuring the port analyzer need to be extended to admit
non-trivial SPAN types.

Create a structure where all details of SPAN configuration are kept,
struct mlxsw_sp_span_parms. Also create struct mlxsw_sp_span_entry_ops
to keep per-SPAN-type operations.

Instantiate the latter once for MLXSW_REG_MPAT_SPAN_TYPE_LOCAL_ETH, and
once for a suite of NOP callbacks used for invalidated SPAN entry. Put
the formet as a sole member of a new array mlxsw_sp_span_entry_types,
where all known SPAN types are kept. Introduce a new function,
mlxsw_sp_span_entry_ops(), to look up the right ops suite given a
netdevice.

Change mlxsw_sp_span_mirror_add() to use both parms and ops structures.
Change mlxsw_sp_span_entry_get() and mlxsw_sp_span_entry_create() to
take these as arguments. Modify mlxsw_sp_span_entry_configure() and
mlxsw_sp_span_entry_deconfigure() to dispatch to ops.

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