drm/i915: Remove highly confusing i915_gem_obj_ggtt_pin()

Since i915_gem_obj_ggtt_pin() is an idiom breaking curry function for
i915_gem_object_ggtt_pin(), spare us the confusion and remove it.
Removing it now simplifies later patches to change the i915_vma_pin()
(and friends) interface.

v2: Add a redundant GEM_BUG_ON(!view) to
i915_gem_obj_lookup_or_create_ggtt_vma()

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/1470324762-2545-18-git-send-email-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index a0c95ab..109bb9d 100644
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1270,7 +1270,7 @@
 	if (ret)
 		goto err;
 
-	ret = i915_gem_obj_ggtt_pin(shadow_batch_obj, 0, 0);
+	ret = i915_gem_object_ggtt_pin(shadow_batch_obj, NULL, 0, 0, 0);
 	if (ret)
 		goto err;
 
@@ -1650,7 +1650,7 @@
 		 *   fitting due to fragmentation.
 		 * So this is actually safe.
 		 */
-		ret = i915_gem_obj_ggtt_pin(obj, 0, 0);
+		ret = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, 0);
 		if (ret)
 			goto err;