drm/tilcdc: Remove tilcdc panel driver

drm/tilcdc: Remove tilcdc panel driver

The tilcdc panel subdriver is a legacy, non-standard driver that has been
replaced by the standard panel-dpi driver and panel-simple infrastructure.

With the device tree bindings removed and all in-tree users migrated to
use panel-dpi, this driver no longer has any associated device tree
bindings or users. The panel-dpi driver combined with DRM bus flags
provides equivalent functionality in a standard way that is compatible
with the broader DRM panel ecosystem.

This removal eliminates 400+ lines of redundant code and completes the
migration to standard panel handling.

Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Kory Maincent (TI.com) <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20260123-feature_tilcdc-v5-6-5a44d2aa3f6f@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>