Add the usual trampoline functionality from the generic DSA layer down
to the drivers for MST state changes.

When a state changes to disabled/blocking/listening, make sure to fast
age any dynamic entries in the affected VLANs (those controlled by the
MSTI in question).
Signed-off-by: NTobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: NVladimir Oltean <olteanv@gmail.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>