drm/i915: move all rps state into dev_priv->rps

This way it's easier so see what belongs together, and what is used
by the ilk ips code. Also add some comments that explain the locking.

Note that (cur|min|max)_delay need to be duplicated, because
they're also used by the ips code.

v2: Missed one place that the dev_priv->ips change caught ...

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 26a2cf6..1614097 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -819,9 +819,21 @@
 
 	bool mchbar_need_disable;
 
-	struct work_struct rps_work;
-	spinlock_t rps_lock;
-	u32 pm_iir;
+	/* gen6+ rps state */
+	struct {
+		struct work_struct work;
+		u32 pm_iir;
+		/* lock - irqsave spinlock that protectects the work_struct and
+		 * pm_iir. */
+		spinlock_t lock;
+
+		/* The below variables an all the rps hw state are protected by
+		 * dev->struct mutext. */
+		u8 cur_delay;
+		u8 min_delay;
+		u8 max_delay;
+	} rps;
+
 
 	u8 cur_delay;
 	u8 min_delay;