[hrtimer] Change resolution storage to ktime_t format

Change the storage format of the per base resolution to ktime_t to
make it easier accessible in the hrtimers code.

Change the resolution from (NSEC_PER_SEC/HZ) to TICK_NSEC as Roman
pointed out. TICK_NSEC is closer to the real resolution.

Signed-off-by: Thomas Gleixner <[email protected]>

include/linux/hrtimer.h

@@ -85,7 +85,7 @@ struct hrtimer_base {
 	spinlock_t		lock;
 	struct rb_root		active;
 	struct rb_node		*first;
-	unsigned long		resolution;
+	ktime_t			resolution;
 	ktime_t			(*get_time)(void);
 	struct hrtimer		*curr_timer;
 };