drm: Remove unused drm_device from drm_gem_object_lookup()

drm_gem_object_lookup() has never required the drm_device for its file
local translation of the user handle to the GEM object. Let's remove the
unused parameter and save some space.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: dri-devel@lists.freedesktop.org
Cc: Dave Airlie <airlied@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Fixup kerneldoc too.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index a965e7e..c3379226 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1141,7 +1141,7 @@
 	if (width > AST_MAX_HWC_WIDTH || height > AST_MAX_HWC_HEIGHT)
 		return -EINVAL;
 
-	obj = drm_gem_object_lookup(crtc->dev, file_priv, handle);
+	obj = drm_gem_object_lookup(file_priv, handle);
 	if (!obj) {
 		DRM_ERROR("Cannot find cursor object %x for crtc\n", handle);
 		return -ENOENT;