net: mscc: ocelot: keep traps in a list

When using the ocelot-8021q tagging protocol, the CPU port isn't
configured as an NPI port, but is a regular port. So a "trap to CPU"
operation is actually a "redirect" operation. So DSA needs to set up the
trapping action one way or another, depending on the tagging protocol in
use.

To ease DSA's work of modifying the action, keep all currently installed
traps in a list, so that DSA can live-patch them when the tagging
protocol changes.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>