drm/imx: Use DRM_PLANE_COMMIT_NO_DISABLE_AFTER_MODESET flag

The IPUv3 display controller behind imx-drm needs all planes of
a CRTC be disabled when the CRTC is disabled.
The DRM_PLANE_COMMIT_NO_DISABLE_AFTER_MODESET flag reflects this
hardware requirement.  Let's use the flag for imx-drm.

Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Peter Senna Tschudin <peter.senna@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Liu Ying <gnuiyl@gmail.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>