s390: use false/true when using bool

Yet another trivial patch to reduce the noise that coccinelle
generates.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index 52949df..eebbd6a 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -492,7 +492,7 @@ static void __init stp_reset(void)
 		pr_warn("The real or virtual hardware system does not provide an STP interface\n");
 		free_page((unsigned long) stp_page);
 		stp_page = NULL;
-		stp_online = 0;
+		stp_online = false;
 	}
 }