[llvm] [LV] Fix '-1U' bits for smallest type in getSmallestAndWidestTypes (PR #135783)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `arc-builder` running on `arc-worker` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/3/builds/14674

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
...
..............................................................................................................................................................
----------------------------------------------------------------------
Ran 158 tests in 2.494s

OK
10.643 [31/18/30] Linking CXX executable unittests/Debuginfod/DebuginfodTests
11.126 [30/18/31] Linking CXX executable unittests/DebugInfo/PDB/DebugInfoPDBTests
11.746 [29/18/32] Linking CXX executable unittests/ExecutionEngine/JITLink/JITLinkTests
11.894 [28/18/33] Linking CXX executable unittests/ExecutionEngine/ExecutionEngineTests
12.283 [27/18/34] Linking CXX executable unittests/InterfaceStub/InterfaceStubTests
command timed out: 1200 seconds without output running [b'ninja', b'check-all'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1213.276590

```

</details>

https://github.com/llvm/llvm-project/pull/135783