net: lan966x: Fix port police support using tc-matchall

When the police was removed from the port, then it was trying to
remove the police from the police id and not from the actual
police index.
The police id represents the id of the police and police index
represents the position in HW where the police is situated.
The port police id can be any number while the port police index
is a number based on the port chip port.
Fix this by deleting the police from HW that is situated at the
police index and not police id.

Fixes: 5390334b ("net: lan966x: Add port police support using tc-matchall")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>