drm/i915: unify ring irq refcounts (again)

With the simplified locking there's no reason any more to keep the
refcounts seperate.

v2: Readd the lost comment that ring->irq_refcount is protected by
dev_priv->irq_lock.

Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 8a87b3f..6e38256 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -78,10 +78,7 @@
 	 */
 	u32		last_retired_head;
 
-	struct {
-		u32	gt; /*  protected by dev_priv->irq_lock */
-		u32	pm; /*  protected by dev_priv->irq_lock */
-	} irq_refcount;
+	unsigned irq_refcount; /* protected by dev_priv->irq_lock */
 	u32		irq_enable_mask;	/* bitmask to enable ring interrupt */
 	u32		trace_irq_seqno;
 	u32		sync_seqno[I915_NUM_RINGS-1];