[llvm] [MSan] Update type for MsanMetadataPtrForLoadN and MsanMetadataPtrForStoreN (PR #135040)

[Vitaly Buka via llvm-commits]

https://github.com/vitalybuka approved this pull request.

This is for Kernel and it's declared there as uintptr_t, so LGTM.

https://github.com/llvm/llvm-project/pull/135040