aco: don't use SMEM for SSBO stores

aco: don't use SMEM for SSBO stores

fossil-db (Navi):
Totals from 70 (0.05% of 138791) affected shaders:
SGPRs: 2324 -> 2097 (-9.77%)
VGPRs: 1344 -> 1480 (+10.12%)
CodeSize: 157872 -> 154836 (-1.92%); split: -1.93%, +0.01%
MaxWaves: 1288 -> 1260 (-2.17%)
Instrs: 29730 -> 29108 (-2.09%); split: -2.13%, +0.04%
Cycles: 394944 -> 391280 (-0.93%); split: -0.94%, +0.01%
VMEM: 5288 -> 5695 (+7.70%); split: +11.97%, -4.27%
SMEM: 2680 -> 2444 (-8.81%); split: +1.34%, -10.15%
VClause: 291 -> 502 (+72.51%)
SClause: 1176 -> 918 (-21.94%)
Copies: 3549 -> 3517 (-0.90%); split: -1.80%, +0.90%
Branches: 1230 -> 1228 (-0.16%)
PreSGPRs: 1675 -> 1491 (-10.99%)
PreVGPRs: 1101 -> 1223 (+11.08%)

Totals from 70 (0.05% of 139517) affected shaders (RAVEN):
SGPRs: 2368 -> 2121 (-10.43%)
VGPRs: 1344 -> 1480 (+10.12%)
CodeSize: 156664 -> 153252 (-2.18%)
MaxWaves: 636 -> 622 (-2.20%)
Instrs: 29968 -> 29226 (-2.48%)
Cycles: 398284 -> 393492 (-1.20%)
VMEM: 5544 -> 5930 (+6.96%); split: +11.72%, -4.76%
SMEM: 2752 -> 2502 (-9.08%); split: +1.20%, -10.28%
VClause: 292 -> 504 (+72.60%)
SClause: 1236 -> 940 (-23.95%)
Copies: 3907 -> 3852 (-1.41%); split: -2.20%, +0.79%
Branches: 1230 -> 1228 (-0.16%)
PreSGPRs: 1671 -> 1487 (-11.01%)
PreVGPRs: 1102 -> 1225 (+11.16%)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6143>