drm: renesas: shmobile: Remove backlight support

Backlight support should be implemented by panels, not by the LCDC
driver. As the feature is currently unused anyway, remove it.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
[geert: Cleanups]
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/69707650245bc2193d072f24723d4d5482ea590b.1694767209.git.geert+renesas@glider.be

drm: Place Renesas drivers in a separate dir

Create vendor specific renesas directory and move renesas drivers
to that directory.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Acked-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>