[amdgpu] Fix scoreboard updating on `s_waitcnt_vscnt`.

Summary: - Other counters are accidentally cleared.

Subscribers: arsenm, kzhuravl, jvesely, wdng, nhaehnle, yaxunl, dstuttard, tpr, t-tye, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D71866