net: dsa: b53: VLAN filtering is global to all users

net: dsa: b53: VLAN filtering is global to all users

The bcm_sf2 driver uses the b53 driver as a library but does not make
usre of the b53_setup() function, this made it fail to inherit the
vlan_filtering_is_global attribute. Fix this by moving the assignment to
b53_switch_alloc() which is used by bcm_sf2.

Fixes: 52afcc6699c9 ("net: dsa: b53: Let DSA handle mismatched VLAN filtering settings")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>