drm/i915/lspcon: do not hardcode settle timeout

Avoid hardcoding the LSPCON settle timeout because it takes a longer
time on certain chips made by certain vendors. Use the function that
already exists to determine the timeout.

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Signed-off-by: Giedrius Statkevičius <giedriuswork@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241017075725.207384-1-giedriuswork@gmail.com


Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>