drm/i915/userptr: Convert to drm_i915_private

userptr directly only uses drm_device in a single interface where it
meant to use drm_i915_private (everywhere else we have to derive it from
the drm_i915_gem_object and so require going from drm_device).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463671036-3235-1-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.h

@@ -2961,7 +2961,7 @@ int i915_gem_set_tiling(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
 int i915_gem_get_tiling(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
-int i915_gem_init_userptr(struct drm_device *dev);
+void i915_gem_init_userptr(struct drm_i915_private *dev_priv);
 int i915_gem_userptr_ioctl(struct drm_device *dev, void *data,
 			   struct drm_file *file);
 int i915_gem_get_aperture_ioctl(struct drm_device *dev, void *data,

drivers/gpu/drm/i915/i915_gem.c

@@ -4913,10 +4913,7 @@ int i915_gem_init(struct drm_device *dev)
 	 */
 	intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
 
-	ret = i915_gem_init_userptr(dev);
-	if (ret)
-		goto out_unlock;
-
+	i915_gem_init_userptr(dev_priv);
 	i915_gem_init_ggtt(dev);
 
 	ret = i915_gem_context_init(dev);

drivers/gpu/drm/i915/i915_gem_userptr.c

@@ -855,11 +855,8 @@ i915_gem_userptr_ioctl(struct drm_device *dev, void *data, struct drm_file *file
 	return 0;
 }
 
-int
-i915_gem_init_userptr(struct drm_device *dev)
+void i915_gem_init_userptr(struct drm_i915_private *dev_priv)
 {
-	struct drm_i915_private *dev_priv = to_i915(dev);
 	mutex_init(&dev_priv->mm_lock);
 	hash_init(dev_priv->mm_structs);
-	return 0;
 }