[llvm] [LoongArch] Allow delayed decision for ADD/SUB relocations (PR #72960)

[Lu Weining via llvm-commits]

SixWeining wrote:

> $ clang --target=loongarch64 -g -O2 -c -o /dev/null vgettimeofday.i
> error: .uleb128 expression is not absolute
> error: .uleb128 expression is not absolute
> 2 errors generated.

Seems that this reduced case and buildbot failures (https://lab.llvm.org/staging/#/builders/106/builds/2820) have been addressed by 0731567a31e4ade97c27801045156a88c4589704. But I'm not sure about the vDSO case.

https://github.com/llvm/llvm-project/pull/72960