drm/i915: remove unused HAS_BROKEN_CS_TLB()

The last users have been removed years ago. Finish the job.

Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240731110744.1572240-1-jani.nikula@intel.com


Signed-off-by: Jani Nikula <jani.nikula@intel.com>