intel/fs: improve Wa_22013689345 workaround

intel/fs: improve Wa_22013689345 workaround

The initial implementation is a pretty big hammer. Implement the HW
recommendation to minimize cases in which we need a fence.

This improves by 10FPS on some of the Sascha Willems RT demos.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 6031ad4bf690 ("intel/fs: Add Wa_22013689345")
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19322>
(cherry picked from commit 945637514e6e970fcc37745f509eec11ff3b5129)