drm/i915/pcode: drop fast wait from snb_pcode_write_timeout()

drm/i915/pcode: drop fast wait from snb_pcode_write_timeout()

Only use the ms granularity wait in snb_pcode_write_timeout(), primarily
to better align with the xe driver, which also only has the millisecond
wait.

Use an arbitrary 250 us fast wait before the specified ms wait, and have
snb_pcode_write() default to 1 ms.

This means snb_pcode_write() and snb_pcode_write_timeout() will always
be sleeping functions. There should not be any atomic users for pcode
writes though, and any display code using pcode via xe has already been
non-atomic. The uncore wait will do a might_sleep() annotation that
should catch any problems.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/ba86280f53cea2d020308db35f1ecbd615d07d8a.1750678991.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>