net: mscc: ocelot: consolidate cookie allocation for private VCAP rules

Every use case that needed VCAP filters (in order: DSA tag_8021q, MRP,
PTP traps) has hardcoded filter identifiers that worked well enough for
that use case alone. But when two or more of those use cases would be
used together, some of those identifiers would overlap, leading to
breakage.

Add definitions for each cookie and centralize them in ocelot_vcap.h,
such that the overlaps are more obvious.

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