[llvm] [BPF] Report warning for some insn imm requiring int range in inline asm (PR #142989)

[via llvm-commits]

eddyz87 wrote:

There are quite a few kernel selftests failing to build because of the -Werror:

```
progs/dummy_st_ops_success.c
progs/dynptr_fail.c
progs/iters.c
progs/verifier_and.c
progs/verifier_array_access.c
progs/verifier_bounds.c
progs/verifier_direct_packet_access.c
progs/verifier_ldsx.c
progs/verifier_masking.c
progs/verifier_movsx.c
progs/verifier_or_jmp32_k.c
progs/verifier_raw_stack.c
progs/verifier_search_pruning.c
progs/verifier_spill_fill.c
progs/verifier_stack_ptr.c
progs/verifier_subreg.c
progs/verifier_unpriv.c
```

But all seem to be legit warnings for statements like: `r1 = 0xffffffff`.

https://github.com/llvm/llvm-project/pull/142989