sched: cleanup, use NSEC_PER_MSEC and NSEC_PER_SEC

1) hardcoded 1000000000 value is used five times in places where
   NSEC_PER_SEC might be more readable.

2) A conversion from nsec to msec uses the hardcoded 1000000 value,
   which is a candidate for NSEC_PER_MSEC.

no code changed:

    text    data     bss     dec     hex filename
   44359    3326      36   47721    ba69 sched.o.before
   44359    3326      36   47721    ba69 sched.o.after

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 6e3b63c..adddf68 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -226,9 +226,9 @@
 
 #ifdef CONFIG_SCHED_DEBUG
 static unsigned long min_sched_granularity_ns = 100000;		/* 100 usecs */
-static unsigned long max_sched_granularity_ns = 1000000000;	/* 1 second */
+static unsigned long max_sched_granularity_ns = NSEC_PER_SEC;	/* 1 second */
 static unsigned long min_wakeup_granularity_ns;			/* 0 usecs */
-static unsigned long max_wakeup_granularity_ns = 1000000000;	/* 1 second */
+static unsigned long max_wakeup_granularity_ns = NSEC_PER_SEC;	/* 1 second */
 #endif
 
 static struct ctl_table kern_table[] = {