[llvm] [AMDGPU] s_quadmask* implicitly defines SCC (PR #161582)

[via llvm-commits]

LU-JOHN wrote:

Prior to this PR the assembly generated for scc_quadmask.ll was:

```
        s_bitcmp0_b32 s0, 0
        s_quadmask_b32 s0, s1
        v_mov_b32_e32 v3, s0
        s_cselect_b64 s[0:1], -1, 0
```

https://github.com/llvm/llvm-project/pull/161582