net: Decouple HK_FLAG_WQ and HK_FLAG_DOMAIN cpumask fetch

To prepare for supporting each feature of the housekeeping cpumask
toward cpuset, prepare each of the HK_FLAG_* entries to move to their
own cpumask with enforcing to fetch them individually. The new
constraint is that multiple HK_FLAG_* entries can't be mixed together
anymore in a single call to housekeeping cpumask().

This will later allow, for example, to runtime modify the cpulist passed
through "isolcpus=", "nohz_full=" and "rcu_nocbs=" kernel boot
parameters.

Signed-off-by: Frederic Weisbecker <[e-mail]>
Signed-off-by: Peter Zijlstra (Intel) <[e-mail]>
Reviewed-by: Juri Lelli <[e-mail]>
Reviewed-by: Phil Auld <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

net/core/net-sysfs.c

···
 {
 	struct rps_map *old_map, *map;
 	cpumask_var_t mask;
-	int err, cpu, i, hk_flags;
+	int err, cpu, i;
 	static DEFINE_MUTEX(rps_map_mutex);
 
 	if (!capable(CAP_NET_ADMIN))
···
 	}
 
 	if (!cpumask_empty(mask)) {
-		hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
-		cpumask_and(mask, mask, housekeeping_cpumask(hk_flags));
+		cpumask_and(mask, mask, housekeeping_cpumask(HK_FLAG_DOMAIN));
+		cpumask_and(mask, mask, housekeeping_cpumask(HK_FLAG_WQ));
 		if (cpumask_empty(mask)) {
 			free_cpumask_var(mask);
 			return -EINVAL;