mt7530 mt7530_fdb_write only set ivl bit vid larger than 1

Fixes my earlier patch which broke vlan unaware bridges.

The IVL bit now only gets set for vid's larger than 1.

Fixes: 11d8d98c

 ("mt7530 fix mt7530_fdb_write vid missing ivl bit")
Signed-off-by: Eric Woudstra <ericwouds@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>