drm/i2c: adv7511: Add Audio support.

This patch adds support to Audio for both adv7511 and adv7533 bridge
chips. Content of this patch is has copied from [1].

[1] https://github.com/analogdevicesinc/linux/blob/xcomm_zynq/drivers/gpu/drm/i2c/adv7511_audio.c



Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
[Srinivas Kandagatla] Adapted to new adv7511 bridge driver.
Signed-off-by: Archit Taneja <architt@codeaurora.org>