drm/i915: Rename request->ringbuf to request->ring

Now that we have disambuigated ring and engine, we can use the clearer
and more consistent name for the intel_ringbuffer pointer in the
request.

@@
struct drm_i915_gem_request *r;
@@
- r->ringbuf
+ r->ring

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469432687-22756-12-git-send-email-chris@chris-wilson.co.uk
Link: http://patchwork.freedesktop.org/patch/msgid/1470174640-18242-2-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index a0e24eb..f7f4a8c 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -552,7 +552,7 @@
 mi_set_context(struct drm_i915_gem_request *req, u32 hw_flags)
 {
 	struct drm_i915_private *dev_priv = req->i915;
-	struct intel_ringbuffer *ring = req->ringbuf;
+	struct intel_ringbuffer *ring = req->ring;
 	struct intel_engine_cs *engine = req->engine;
 	u32 flags = hw_flags | MI_MM_SPACE_GTT;
 	const int num_rings =
@@ -655,7 +655,7 @@
 static int remap_l3(struct drm_i915_gem_request *req, int slice)
 {
 	u32 *remap_info = req->i915->l3_parity.remap_info[slice];
-	struct intel_ringbuffer *ring = req->ringbuf;
+	struct intel_ringbuffer *ring = req->ring;
 	int i, ret;
 
 	if (!remap_info)