We don't need to keep empty callbacks for the (pre/post) enable/disable
drm_bridge ops anymore. Remove the nop callback used here for
pre_enable and post_disable ops.
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1459329804-10488-1-git-send-email-architt@codeaurora.org