mlxsw: spectrum: Extend and export SPAN API

Extend SPAN API for ACL case. In case of ACL triggering the MPAR register
shouldn't be configured. This patch also export those helpers for
ACL usage.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>