drm/i915/client: only include what's needed

Only the uapi header is required.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220607092207.476653-1-jani.nikula@intel.com