net: dsa: felix: migrate flood settings from NPI to tag_8021q CPU port

When the tagging protocol changes from "ocelot" to "ocelot-8021q" or in
reverse, the DSA promiscuity setting that was applied for the old CPU
port must be transferred to the new one.

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