aco: remove p_wqm during insert_exec_mask

fossil-db (navi21):
Totals from 45334 (33.42% of 135636) affected shaders:
MaxWaves: 1062176 -> 1058940 (-0.30%); split: +0.11%, -0.41%
Instrs: 32600411 -> 32541423 (-0.18%); split: -0.20%, +0.02%
CodeSize: 176449880 -> 175931224 (-0.29%); split: -0.32%, +0.03%
VGPRs: 2074768 -> 2093040 (+0.88%); split: -0.18%, +1.06%
Latency: 445697225 -> 445555067 (-0.03%); split: -0.10%, +0.06%
InvThroughput: 84125135 -> 84512709 (+0.46%); split: -0.22%, +0.68%
VClause: 629965 -> 621630 (-1.32%); split: -1.75%, +0.43%
SClause: 1423941 -> 1415971 (-0.56%); split: -0.84%, +0.28%
Copies: 1871955 -> 1820874 (-2.73%); split: -3.03%, +0.30%
Branches: 652251 -> 652168 (-0.01%); split: -0.02%, +0.01%
PreVGPRs: 1775517 -> 1772710 (-0.16%)

fossil-db (navi21, excluding detroit: become human):
Totals from 37943 (33.14% of 114495) affected shaders:
MaxWaves: 942546 -> 943090 (+0.06%); split: +0.12%, -0.06%
Instrs: 20810132 -> 20765529 (-0.21%); split: -0.24%, +0.03%
CodeSize: 112843980 -> 112508644 (-0.30%); split: -0.34%, +0.04%
VGPRs: 15803048 -> 1582736 (+0.15%); split: -0.22%, +0.37%
Latency: 282400557 -> 282276594 (-0.04%); split: -0.14%, +0.10%
InvThroughput: 54958538 -> 54814378 (-0.26%); split: -0.32%, +0.06%
VClause: 420666 -> 422099 (+0.34%); split: -0.27%, +0.61%
SClause: 988189 -> 981029 (-0.72%); split: -1.11%, +0.38%
Copies: 1009518 -> 970925 (-3.82%); split: -4.26%, +0.44%
Branches: 306082 -> 306083 (+0.00%); split: -0.01%, +0.01%
PreVGPRs: 1286421 -> 1283757 (-0.21%)

Detroit: Become Human MaxWaves regressions seem to be due to the scheduler
choosing to schedule more aggressively.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>