s390/time: rename tod clock access functions

Fix name clash with some common code device drivers and add "tod"
to all tod clock access function names.

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/vtime.c b/arch/s390/kernel/vtime.c
index e84b8b6..8911a16 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -191,7 +191,7 @@
 	unsigned int sequence;
 
 	do {
-		now = get_clock();
+		now = get_tod_clock();
 		sequence = ACCESS_ONCE(idle->sequence);
 		idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
 		idle_exit = ACCESS_ONCE(idle->clock_idle_exit);