linux-imx

drm/imx: dpu: crtc: Wait for FrameGen secondary syncup in ->atomic_enable()

Although the hardware spec doesn't mention the additional operation to
wait for FrameGen secondary syncup for FrameGen non-sync mode when we
enable a display, it doesn't hurt to do it and we may get warning message
in case it's not syncup.

Signed-off-by: Liu Ying <victor.liu@nxp.com>