drm/i2c: adv7511: setup CEC registers during power off-power-on sequence

This patch sets up the CEC register during power up sequence, the reason
to do this because during power dowm the bridge can put audio pins in to
low power state.

Orignally the issue was detected on ubuntu image, where in after first
logout the audio was totally disabled.

Reported-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>