The ingress filter registers use 2 bits for each port to define the filtering
state, whereas the egress filter uses 1 bit. So for for the ingress filter
the register offset for a given port is:
(port >> 4) << 4: since there are 16 entries in a register of 32 bits
and for the egress filter:
(port >> 5) << 4: since there are 32 entries in a register of 32 bits
Signed-off-by: Birger Koblitz <git@birger-koblitz.de>