[S390] pfault: always enable service signal interrupt

Always enable the service signal subclass mask bit in cr0, if pfault
is available. That way we use the normal cpu hotplug way to propagate
the subclass mask bit in cr0 instead of open coding it.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/mm/fault.c

@@ -485,7 +485,6 @@ int pfault_init(void)
 		"2:\n"
 		EX_TABLE(0b,1b)
 		: "=d" (rc) : "a" (&refbk), "m" (refbk) : "cc");
-        __ctl_set_bit(0, 9);
         return rc;
 }
 
@@ -500,7 +499,6 @@ void pfault_fini(void)
 
 	if (!MACHINE_IS_VM || pfault_disable)
 		return;
-	__ctl_clear_bit(0,9);
 	asm volatile(
 		"	diag	%0,0,0x258\n"
 		"0:\n"
@@ -615,6 +613,7 @@ static int __init pfault_irq_init(void)
 	rc = pfault_init() == 0 ? 0 : -EOPNOTSUPP;
 	if (rc)
 		goto out_pfault;
+	ctl_set_bit(0, 9);
 	hotcpu_notifier(pfault_cpu_notify, 0);
 	return 0;