net: mscc: ocelot: avoid overlap in VCAP IS2 between PTP and MRP traps

OCELOT_VCAP_IS2_TAG_8021Q_TXVLAN overlaps with OCELOT_VCAP_IS2_MRP_REDIRECT.
To avoid this, make OCELOT_VCAP_IS2_MRP_REDIRECT take the cookie region
from N to 2 * N - 1 (where N is ocelot->num_phys_ports).

To avoid any risk that the singleton (not per port) VCAP IS2 filters
overlap with per-port VCAP IS2 filters, we must ensure that the number
of singleton filters is smaller than the number of physical ports.
This is true right now, but may change in the future as switches with
less ports get supported, or more singleton filters get added. So to be
future-proof, let's move the singleton filters at the end of the range,
where they won't overlap with anything to their right.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>