power: fix multi-queue scale mode

power: fix multi-queue scale mode

Currently in scale mode, multi-queue initialization will attempt to
initialize and de-initialize the per-lcore power library structures
multiple times. Fix it to only do this whenever we either enabling
first queue or disabling last queue.

Fixes: 5dff9a72b0ef ("power: support callbacks for multiple Rx queues")

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Tested-by: David Hunt <david.hunt@intel.com>