drm/sun4i: wait on implicit fence before display Render like lima will attach a fence to the framebuffer dma_buf, display like sun4i should wait it finish before show the framebuffer. Otherwise tearing will be observed. Signed-off-by: Qiang Yu <[email protected]> Signed-off-by: Daniel Vetter <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]