mvpp2: refactor BM pool functions

Refactor mvpp2_bm_pool_create(), mvpp2_bm_pool_destroy() and
mvpp2_bm_pools_init() so that they accept a struct device instead
of a struct platform_device, as they just need platform_device->dev.

Removing such dependency makes the BM code more reusable in context
where we don't have a pointer to the platform_device.

Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>