drm: adv7511: Add support for i2c_new_secondary_device

The ADV7511 has four 256-byte maps that can be accessed via the main I2C
ports. Each map has it own I2C address and acts as a standard slave
device on the I2C bus.

Allow a device tree node to override the default addresses so that
address conflicts with other devices on the same bus may be resolved at
the board description level.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1518544137-2742-6-git-send-email-kbingham@kernel.org