drm/tilcdc: Remove unnecessary tilcdc_crtc_disable() from tilcdc_unload()

Remove unnecessary tilcdc_crtc_disable() from tilcdc_unload(). The
tilcdc_crtc_disable() called via tilcdc_crtc_destroy() by
drm_mode_config_cleanup() couple of lines later.

The early call to tilcdc_crtc_disable() was a wrong fix (that worked)
for calling drm_flip_work_cleanup() before flushing the flip-work
queue.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>