drm/i915/tc: use generic poll_timeout_us() instead of wait_for()

drm/i915/tc: use generic poll_timeout_us() instead of wait_for()

Prefer generic poll helpers over i915 custom helpers.

The functional change is losing the exponentially growing sleep of
wait_for(), which used to be 10, 20, 40, ..., 640, and 1280 us.

Use an arbitrary constant 200 us sleep for the 5 ms timeout, and 1000 us
sleep for the 500 ms timeout. The timeouts remain the same.

Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://lore.kernel.org/r/50cd06b61210f541d5bb52a36af2d8bf059dd3a1.1756383233.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>