uml: use *SEC_PER_*SEC constants

There are various uses of powers of 1000, plus the odd BILLION constant in the
time code.  However, there are perfectly good definitions of *SEC_PER_*SEC in
linux/time.h which can be used instaed.

These are replaced directly in kernel code.  Userspace code imports those
constants as UM_*SEC_PER_*SEC and uses these.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 2acdc7e..1ac746a 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -17,7 +17,7 @@
  */
 unsigned long long sched_clock(void)
 {
-	return (unsigned long long)jiffies_64 * (1000000000 / HZ);
+	return (unsigned long long)jiffies_64 * (NSEC_PER_SEC / HZ);
 }
 
 void timer_handler(int sig, struct uml_pt_regs *regs)
@@ -118,8 +118,9 @@
 	timer_init();
 
 	nsecs = os_nsecs();
-	set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION,
-				-nsecs % BILLION);
-	set_normalized_timespec(&xtime, nsecs / BILLION, nsecs % BILLION);
+	set_normalized_timespec(&wall_to_monotonic, -nsecs / NSEC_PER_SEC,
+				-nsecs % NSEC_PER_SEC);
+	set_normalized_timespec(&xtime, nsecs / NSEC_PER_SEC,
+				nsecs % NSEC_PER_SEC);
 	late_time_init = setup_itimer;
 }