Revert "vmstat: disable vmstat_work on vmstat_cpu_down_prep()"

This reverts commit adcfb26.

It turns out this just causes a different warning splat instead that
seems to be much easier to trigger, so let's revert ASAP.

Reported-and-bisected-by: Borislav Petkov <bp@alien8.de>
Tested-by: Breno Leitao <leitao@debian.org>
Reported-by: Alexander Gordeev <agordeev@linux.ibm.com>
Link: https://lore.kernel.org/all/20250106131817.GAZ3vYGVr3-hWFFPLj@fat_crate.local/
Cc: Koichiro Den <koichiro.den@canonical.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: torvalds

mm/vmstat.c

@@ -2148,14 +2148,13 @@ static int vmstat_cpu_online(unsigned int cpu)
 	if (!node_state(cpu_to_node(cpu), N_CPU)) {
 		node_set_state(cpu_to_node(cpu), N_CPU);
 	}
-	enable_delayed_work(&per_cpu(vmstat_work, cpu));
 
 	return 0;
 }
 
 static int vmstat_cpu_down_prep(unsigned int cpu)
 {
-	disable_delayed_work_sync(&per_cpu(vmstat_work, cpu));
+	cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));
 	return 0;
 }