0a089b1b13
The barrier half is HW scoreboarded by the GPR isn't. When moving from
a GPR to a barrier, we still need a token for WaR hazards.
Fixes: 7cd9680554 ("nak: Add back OpBMov with better semantics")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/29591>