[llvm] [LoongArch] Support R_LARCH_{ADD, SUB}_ULEB128 for .uleb128 and force relocs when sym is not in section (PR #76433)

[Nathan Chancellor via llvm-commits]

nathanchance wrote:

I can confirm that this change resolves the issue I reported at https://github.com/llvm/llvm-project/pull/72960#issuecomment-1866844679 and the resulting kernel boots in QEMU. I am not really qualified to comment on this patch beyond that though.

https://github.com/llvm/llvm-project/pull/76433