drm/i915: Use engine to refer to the user's BSD intel_engine_cs

This patch transitions the execbuf engine selection away from using the
ring nomenclature - though we still refer to the user's incoming
selector as their user_ring_id.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1469432687-22756-7-git-send-email-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469606850-28659-2-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 3730aec..e155e8d 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4782,7 +4782,7 @@
 	spin_lock_init(&file_priv->mm.lock);
 	INIT_LIST_HEAD(&file_priv->mm.request_list);
 
-	file_priv->bsd_ring = -1;
+	file_priv->bsd_engine = -1;
 
 	ret = i915_gem_context_open(dev, file);
 	if (ret)