drm: i915: Use nsec based interfaces

Use ktime_get_raw_ns() and get rid of the back and forth timespec
conversions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: John Stultz <john.stultz@linaro.org>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 374f964..1f77008 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -931,7 +931,7 @@
 	unsigned long last_time1;
 	unsigned long chipset_power;
 	u64 last_count2;
-	struct timespec last_time2;
+	u64 last_time2;
 	unsigned long gfx_power;
 	u8 corr;