net: dsa: felix: remove ocelot->npi assignment from felix_8021q_cpu_port_init

This assignment is redundant, since ocelot->npi has already been set to
-1 by felix_npi_port_deinit(). Call path:

felix_change_tag_protocol
-> felix_del_tag_protocol(DSA_TAG_PROTO_OCELOT)
   -> felix_teardown_tag_npi
      -> felix_npi_port_deinit
-> felix_set_tag_protocol(DSA_TAG_PROTO_OCELOT_8021Q)
   -> felix_setup_tag_8021q
      -> felix_8021q_cpu_port_init

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