drm/radeon: add GART debugfs access v3

v2: add default_llseek
v3: set inode size in the open callback

Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 49f210c1..572476b 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -416,6 +416,7 @@
 
 #if defined(CONFIG_DEBUG_FS)
 	struct dentry			*vram;
+	struct dentry			*gtt;
 #endif
 };