drm/bridge: analogix-anx78xx: silence -EPROBE_DEFER warnings

Silence two warning messages that occur due to -EPROBE_DEFER errors to
help cleanup the system boot log.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190815004854.19860-4-masneyb@onstation.org