cgroup: adjust criteria for rstat subsystem cpu lock access

Previously it was found that on uniprocessor machines the size of
raw_spinlock_t could be zero so a pre-processor conditional was used to
avoid the allocation of ss->rstat_ss_cpu_lock. The conditional did not take
into account cases where lock debugging features were enabled. Cover these
cases along with the original non-smp case by explicitly using the size of
size of the lock type as criteria for allocation/access where applicable.

Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Fixes: 748922dc "cgroup: use subsystem-specific rstat locks to avoid contention"
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202505281034.7ae1668d-lkp@intel.com


Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>