drm/vc4: Fix errant drm_bridge_remove() in DSI.

drm_bridge_remove() is for unregistering a bridge driver, not for
detaching a bridge from its consumer.

Fixes: 656fa22f ("drm/vc4: Switch DSI to the panel-bridge layer, and support bridges.")
Signed-off-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20170802203242.12815-3-eric@anholt.net


Acked-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>