net: dsa: bcm_sf2: Allow matching arbitrary IPv6 masks/lengths

There is no reason why we should limit ourselves to matching only
full IPv4 addresses (/32), the same logic applies between the DATA and
MASK ports, so just make it more configurable to accept both.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>