drm/sun4i: dsi: Add a variant structure

Replace the ad-hoc calls to of_device_is_compatible() with a structure
describing the differences between variants. This is in preparation for
adding more variants to the driver.

Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/r/20221107053552.2330-4-samuel@sholland.org


Signed-off-by: Maxime Ripard <maxime@cerno.tech>