net: dsa: felix: stop clearing CPU flooding in felix_setup_tag_8021q

felix_migrate_flood_to_tag_8021q_port() takes care of clearing the
flooding bits on the old CPU port (which was the CPU port module), so
manually clearing this bit from PGID_UC, PGID_MC, PGID_BC is redundant.

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