drm/omap: dss: dsi: Move initialization code from bind to probe

There's no reason to delay initialization of most of the driver (such as
mapping memory I/O or enabling runtime PM) to the component bind
handler. Perform as much of the initialization as possible at probe
time, initializing at bind time only the parts that depends on the DSS.
The cleanup code is moved from unbind to remove in a similar way.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>