drm/tidss: Drop useless variable init

No need to initialize the ret to 0 in dispc_softreset().

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Aradhya Bhatia <a-bhatia1@ti.com>
Link: https://lore.kernel.org/r/20231109-tidss-probe-v2-3-ac91b5ea35c0@ideasonboard.com


Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>