[lld] lld: add SPARC WDISP relocations to lld (PR #206042)

[Jessica Clarke via llvm-commits]

================
@@ -124,6 +132,15 @@ void SPARCV9::relocate(uint8_t *loc, const Relocation &rel,
     checkInt(ctx, loc, val, 21, rel);
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jrtc27 wrote:

```suggestion
    checkInt(ctx, loc, val, 21, rel);
    checkAlignment(ctx, loc, val, 4, rel);
```
given this commit is the first time WDISP19 relocations in input files are handled (currently the only case that gets here is SPARCV9::writePlt which is a multiple of 4 by construction)

https://github.com/llvm/llvm-project/pull/206042