drm/bridge: analogix-anx78xx: add support for 7808 addresses

According to the downstream Android sources, the anx7808 variants use
address 0x78 for TX_P0 and the anx781x variants use address 0x70. Since
the datasheets aren't available for these devices, and we only have the
downstream kernel sources to look at, let's assume that these addresses
are fixed based on the model, and pass the i2c addresses to the driver
via the data pointer in the driver's of_match_table.

Signed-off-by: Brian Masney <masneyb@onstation.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190922175940.5311-1-masneyb@onstation.org