intel/brw: Replace inst F8 macro with F macro

F8 had a case for 4+, 8+ and 12+.  Its uses now can be replaced
with F that has a case for 9+ and 12+.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27691>
1 file changed