drm/i915: Track the enabled PM interrupts in dev_priv.

When we use different rps events for different platforms or due to wa,
we might end up needing this logic in a lot of places. Instead of
this let's use a variable in dev_priv to track the enabled PM
interrupts.

v2: Initialize pm_rps_events in intel_irq_init() (Ville).

Signed-off-by: Deepak S <deepak.s@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[danvet: Frob the commit message a bit since the English was a bit too
garbled ;-) ]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 3f62be0..7b344c5 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1468,6 +1468,7 @@
 	};
 	u32 gt_irq_mask;
 	u32 pm_irq_mask;
+	u32 pm_rps_events;
 	u32 pipestat_irq_mask[I915_MAX_PIPES];
 
 	struct work_struct hotplug_work;