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: 22a920209ab6 ("sched_ext: Implement tickless support")
Signed-off-by: guanjing <[e-mail]>
Acked-by: Andrea Righi <[e-mail]>
Signed-off-by: Tejun Heo <[e-mail]>

tools/sched_ext/scx_central.c

···
 	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);