[ARM] Add sched_clock()

(comments by rmk, patch from Holger Schurig)

sched_clock() needs to be provided by all architectures - this cset
adds support for ARM.

arch/arm/kernel/time.c

@@ -67,6 +67,16 @@ static unsigned long dummy_gettimeoffset(void)
  */
 unsigned long (*gettimeoffset)(void) = dummy_gettimeoffset;
 
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+	unsigned long long this_offset;
+
+	return (unsigned long long)jiffies * (1000000000 / HZ);
+}
+
 /*
  * Handle kernel profile stuff...
  */