eal: fix control threads pinnning

pthread_setaffinity_np returns a >0 value on error.
We could end up letting the ctrl threads on the current process cpu
affinity.

Fixes: d651ee4919 ("eal: set affinity for control threads")
Cc: stable@dpdk.org

Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Olivier Matz <olivier.matz@6wind.com>

lib/librte_eal/common/eal_common_thread.c

@@ -209,7 +209,7 @@ rte_ctrl_thread_create(pthread_t *thread, const char *name,
 		CPU_SET(rte_get_master_lcore(), &cpuset);
 
 	ret = pthread_setaffinity_np(*thread, sizeof(cpuset), &cpuset);
-	if (ret < 0)
+	if (ret)
 		goto fail;
 
 	ret = pthread_barrier_wait(&params->configured);