MLK-19819-1 drm/imx: lcdif: bypass atomic check when CRTC will be disabled

MLK-19819-1 drm/imx: lcdif: bypass atomic check when CRTC will be disabled

On 4.14.y kernel branch, the DRM framework has been modified that
when no CONNECTOR attach to CRTC, the fb creation wil be deferred
until some CONNECTOR has been detected via hotplug. And the system
suspend workflow is also affected accordingly, if the CRTC atomic
check fails, the display-subsystem suspend also will be caused to
fail. So bypass the 'bus_format' check when CRTC is going to be
disabled.

Signed-off-by: Fancy Fang <chen.fang@nxp.com>
(cherry picked from commit 6d54c414c2226bebe7201c69a67891eb4fcc5449)