sched: fix niced_granularity() shift

fix niced_granularity(). This resulted in under-scheduling for
CPU-bound negative nice level tasks (and this in turn caused
higher than necessary latencies in nice-0 tasks).

Signed-off-by: Ingo Molnar <[e-mail]>

kernel/sched_fair.c

···
 	/*
 	 * It will always fit into 'long':
 	 */
-	return (long) (tmp >> WMULT_SHIFT);
+	return (long) (tmp >> (WMULT_SHIFT-NICE_0_SHIFT));
 }
 
 static inline void