drm/radeon: unconfuse return value of radeon_asic->clear_surface_reg

No one cares about it, so set it to void.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 67f3c57..a8552ee 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -783,7 +783,7 @@
 	int (*set_surface_reg)(struct radeon_device *rdev, int reg,
 			       uint32_t tiling_flags, uint32_t pitch,
 			       uint32_t offset, uint32_t obj_size);
-	int (*clear_surface_reg)(struct radeon_device *rdev, int reg);
+	void (*clear_surface_reg)(struct radeon_device *rdev, int reg);
 	void (*bandwidth_update)(struct radeon_device *rdev);
 	void (*hpd_init)(struct radeon_device *rdev);
 	void (*hpd_fini)(struct radeon_device *rdev);