drm/i915: remove i915_gem_object_ggtt_unbind

Only has one user and is nothing more than a shim on top of
i915_vma_unbind, so let's just get rid of it.

Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Suggested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1461842691-27575-1-git-send-email-matthew.auld@intel.com
diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c
index 7410f6c..829dab6 100644
--- a/drivers/gpu/drm/i915/i915_gem_tiling.c
+++ b/drivers/gpu/drm/i915/i915_gem_tiling.c
@@ -229,7 +229,7 @@
 		 */
 		if (obj->map_and_fenceable &&
 		    !i915_gem_object_fence_ok(obj, args->tiling_mode))
-			ret = i915_gem_object_ggtt_unbind(obj);
+			ret = i915_vma_unbind(i915_gem_obj_to_ggtt(obj));
 
 		if (ret == 0) {
 			if (obj->pages &&