[llvm] [AMDGPU] Add missing intrinsic declaration to intrinsics.ll. NFC. (PR #138954)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-aarch64-darwin` running on `doug-worker-4` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/190/builds/19650

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'Clang-Unit :: ./AllClangUnitTests/10/48' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/unittests/./AllClangUnitTests-Clang-Unit-32609-10-48.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=48 GTEST_SHARD_INDEX=10 /Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/unittests/./AllClangUnitTests
--

Script:
--
/Users/buildbot/buildbot-root/aarch64-darwin/build/tools/clang/unittests/./AllClangUnitTests --gtest_filter=DirectoryWatcherTest.ModifyFile
--
/Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp:259: Failure
Value of: WaitForExpectedStateResult.wait_for(EventualResultTimeout) == std::future_status::ready
  Actual: false
Expected: true
The expected result state wasn't reached before the time-out.

/Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp:262: Failure
Value of: TestConsumer.result().has_value()
  Actual: false
Expected: true


/Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp:259
Value of: WaitForExpectedStateResult.wait_for(EventualResultTimeout) == std::future_status::ready
  Actual: false
Expected: true
The expected result state wasn't reached before the time-out.

/Users/buildbot/buildbot-root/aarch64-darwin/llvm-project/clang/unittests/DirectoryWatcher/DirectoryWatcherTest.cpp:262
Value of: TestConsumer.result().has_value()
  Actual: false
Expected: true



********************


```

</details>

https://github.com/llvm/llvm-project/pull/138954