service: fix lcore iteration

service: fix lcore iteration

The service core list is populated, but not used. Incorrect
lcore states are examined for a service.

Use the populated list to iterate over service cores.

Fixes: e484ccddbe1b ("service: avoid false sharing on core state")
Cc: stable@dpdk.org
Signed-off-by: Igor Romanov <igor.romanov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Harry van Haaren <harry.van.haaren@intel.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>