net: mscc: ocelot: use index to set vcap policer

Policer was previously automatically assigned from the highest index to
the lowest index from policer pool. But police action of tc flower now
uses index to set an police entry. This patch uses the police index to
set vcap policers, so that one policer can be shared by multiple rules.

Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>