drm/i2c: adv7511: Initial support for adv7533

ADV7533 is a DSI to HDMI encoder chip. It is a derivative of ADV7511,
with additional blocks to translate input DSI data to parallel RGB
data. Besides the ADV7511 i2c register map, it has additional registers
that require to be configured to activate the DSI blocks.

Use DT compatible strings to populate the adv7533 type enum. Add minimal
register configurations belonging to the DSI/CEC register map.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>