net: microchip: sparx5: add resource pools

Add resource pools and accessor functions. These pools can be queried by
the driver, whenever a finite resource is required. Some resources can
be reused, in which case an index and a reference count is used to keep
track of users.

Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>