net: dsa: bcm_sf2: Get VLAN_PORT_MASK from b53_device

While migrating the bcm_sf2 driver to use b53_common, we left a small
piece untouched where we kept our local copy of the per-port
port_vlan_ctl bitmask value. This value is now maintained by b53_device
so we need to use it instead of our local (and now stale) copy of it.

Fixes: f458995b ("net: dsa: bcm_sf2: Utilize core B53 driver when possible")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>