drm/tilcdc: Remove tilcdc_panel_info structure

drm/tilcdc: Remove tilcdc_panel_info structure

Remove the tilcdc_panel_info structure and its associated helper
function as the structure contains only redundant or unused parameters.

Most panel configuration parameters in tilcdc_panel_info are either:
- Already represented by existing DRM mode flags (invert_pxl_clk,
  sync_edge via DRM_BUS_FLAG_*), or
- Set to identical values across all instances (panel_info_default),
  making them effectively constants

The removed fifo_th field is already handled by priv->fifo_th when set.
Other removed fields (tft_alt_mode, raster_order) were always set to 0
in the only instance (panel_info_default) and thus had no effect.

This simplifies the code by eliminating unnecessary abstraction while
preserving all functional behavior.

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-v5-8-5a44d2aa3f6f@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>