drm/bridge: add anx7625 DSI to DP bridge driver

Add anx7625 bridge driver to support DSI to DP output.
Configure anx7625 chip via I2C for audio/video setup.

CRs-Fixed: 2246610
Change-Id: I25c5a54fc4f6a2f2fc58c8607d81904ac82f46e3
Signed-off-by: Camus Wong <camusw@codeaurora.org>
Signed-off-by: Xiaowen Wu <wxiaowen@codeaurora.org>