drm: use drm_file to tag vm-bos

Rather than using "struct file*", use "struct drm_file*" as tag VM tag for
BOs. This will pave the way for "struct drm_file*" without any "struct
file*" back-pointer.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20160901124837.680-3-dh.herrmann@gmail.com
diff --git a/drivers/gpu/drm/ast/ast_ttm.c b/drivers/gpu/drm/ast/ast_ttm.c
index b29a412..608df4c 100644
--- a/drivers/gpu/drm/ast/ast_ttm.c
+++ b/drivers/gpu/drm/ast/ast_ttm.c
@@ -150,7 +150,8 @@
 {
 	struct ast_bo *astbo = ast_bo(bo);
 
-	return drm_vma_node_verify_access(&astbo->gem.vma_node, filp);
+	return drm_vma_node_verify_access(&astbo->gem.vma_node,
+					  filp->private_data);
 }
 
 static int ast_ttm_io_mem_reserve(struct ttm_bo_device *bdev,