drm/tidss: Add simple K2G manual reset

K2G display controller does not support soft reset, but we can do the
most important steps manually: mask the IRQs and disable the VPs.

Reviewed-by: Aradhya Bhatia <a-bhatia1@ti.com>
Link: https://lore.kernel.org/r/20231109-tidss-probe-v2-7-ac91b5ea35c0@ideasonboard.com


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