[llvm] [libclc] Add missing deps for LLVM_ENABLE_RUNTIMES. (PR #145684)

[Harald van Dijk via llvm-commits]

hvdijk wrote:

When I tried building libclc without this, with `LLVM_ENABLE_RUNTIMES=libclc`, it failed with:
```
[5120/5562] Performing build step for 'runtimes'
ninja: error: '/home/harald/llvm-project/main/build/x86_64-linux-libclc/bin/llvm-link', needed by 'libclc/builtins.link.clc-tahiti-amdgcn--.bc', missing and no known rule to make it
```
because I got unlucky and `llvm-link` had not yet been built at that point.

https://github.com/llvm/llvm-project/pull/145684