drm: omapdrm: dsi: Store DSI model and PLL hardware data in OF data

The DSI PLL hardware data and DSS channels are selected based on the
OMAP SoC model. There's no need for fine-grained model information, as
the driver only needs to differentiate between OMAP3, OMAP4 and OMAP5.
As this can be done through the DSI compatible string, store the
corresponding information in OF match data instead to avoid accessing
the OMAP SoC model.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>