aco/gfx11: workaround VALUMaskWriteHazard

aco/gfx11: workaround VALUMaskWriteHazard

fossil-db (gfx1100):
Totals from 62812 (46.52% of 135032) affected shaders:
Instrs: 43971580 -> 44069887 (+0.22%)
CodeSize: 233473420 -> 233866648 (+0.17%)
Latency: 463487489 -> 463520688 (+0.01%); split: -0.00%, +0.01%
InvThroughput: 86505748 -> 86509679 (+0.00%); split: -0.00%, +0.00%

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18273>