[llvm] [BPF] Use ".L" local prefix label for basic blocks (PR #95103)

[via llvm-commits]

4ast wrote:

> > Okay, looks like current llvm19/llvm20 already do not have L* labels in symbol table. @eddyz87 has another pull request (#100550) to address llvm-objdump without-label issue. There are a couple of options to resolve this. Since we do not want L* in the symbol table, then the only option may be tweak llvm-objdump.
> 
> #100550 is for `llvm-objdump --symbolize-operands`, which creates fake labels for the disassembly output.
> 
> For this patch, I hope we use `.L` to be similar to other ELF architectures and not to create a special case:)

are you saying that if we use ".L" then private labels will automatically appear in disasm output and we don't need this extra flag?
If so let's switch to ".L".

https://github.com/llvm/llvm-project/pull/95103