media: adv7604: Add support for i2c_new_secondary_device

The ADV7604 has thirteen 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.

[Kieran: Re-adapted for mainline]

Signed-off-by: Jean-Michel Hautbois <jean-michel.hautbois@vodalys.com>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>