aco: fix max_waves_per_simd on Polaris, VegaM and GFX10.3

aco: fix max_waves_per_simd on Polaris, VegaM and GFX10.3

fossil-db (Polaris):
Totals from 20263 (14.75% of 137414) affected shaders:
SGPRs: 871407 -> 871679 (+0.03%); split: -0.00%, +0.03%
VGPRs: 513828 -> 550028 (+7.05%); split: -1.68%, +8.72%
CodeSize: 18869680 -> 18828148 (-0.22%); split: -0.23%, +0.01%
MaxWaves: 162012 -> 162030 (+0.01%); split: +0.01%, -0.00%
Instrs: 3629172 -> 3618817 (-0.29%); split: -0.30%, +0.02%
Cycles: 15682244 -> 15638244 (-0.28%); split: -0.30%, +0.02%
VMEM: 10675942 -> 10673344 (-0.02%); split: +0.18%, -0.21%
SMEM: 1209717 -> 1206088 (-0.30%); split: +0.03%, -0.33%
VClause: 81780 -> 81227 (-0.68%); split: -0.73%, +0.06%
SClause: 231724 -> 231561 (-0.07%); split: -0.07%, +0.00%
Copies: 187126 -> 180831 (-3.36%); split: -3.62%, +0.26%
Branches: 26841 -> 26837 (-0.01%); split: -0.03%, +0.01%

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/5546>