cpumask: use topology_core_cpumask/topology_thread_cpumask instead of cpu_core_map/cpu_sibling_map

Impact: cleanup

This is presumably what those definitions are for, and while all archs
define cpu_core_map/cpu_sibling map, that's changing (eg. x86 wants to
change it to a pointer).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/block/blk.h b/block/blk.h
index 0dce92c..3ee9435 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -102,7 +102,7 @@
 	const struct cpumask *mask = cpu_coregroup_mask(cpu);
 	return cpumask_first(mask);
 #elif defined(CONFIG_SCHED_SMT)
-	return first_cpu(per_cpu(cpu_sibling_map, cpu));
+	return cpumask_first(topology_thread_cpumask(cpu));
 #else
 	return cpu;
 #endif