ice: Remove xsk_buff_pool from VSI structure

Current implementation of netdev already contains xsk_buff_pools.
We no longer have to contain these structures in ice_vsi.

Refactor the code to operate on netdev-provided xsk_buff_pools.

Move scheduling napi on each queue to a separate function to
simplify setup function.

Signed-off-by: Michal Swiatkowski <michal.swiatkowski@intel.com>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Kiran Bhandare <kiranx.bhandare@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>