sched_ext: fix application of sizeof to pointer

sizeof when applied to a pointer typed expression gives the size of
the pointer.

The proper fix in this particular case is to code sizeof(*cpuset)
instead of sizeof(cpuset).

This issue was detected with the help of Coccinelle.

Fixes: 22a9202 ("sched_ext: Implement tickless support")
Signed-off-by: guanjing <guanjing@cmss.chinamobile.com>
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Author: guanjing

tools/sched_ext/scx_central.c

@@ -97,7 +97,7 @@ int main(int argc, char **argv)
 	SCX_BUG_ON(!cpuset, "Failed to allocate cpuset");
 	CPU_ZERO(cpuset);
 	CPU_SET(skel->rodata->central_cpu, cpuset);
-	SCX_BUG_ON(sched_setaffinity(0, sizeof(cpuset), cpuset),
+	SCX_BUG_ON(sched_setaffinity(0, sizeof(*cpuset), cpuset),
 		   "Failed to affinitize to central CPU %d (max %d)",
 		   skel->rodata->central_cpu, skel->rodata->nr_cpu_ids - 1);
 	CPU_FREE(cpuset);