[lld] Changing TimeProfiler.cpp clock from microseconds to nanoseconds (PR #68096)

[via llvm-commits]

fel-cab wrote:

At this point, I think this patch is not necessary, given that the events duration in the profiles have to be generated in microseconds, therefore having the times in nanoseconds do not have any benefit. For this reason, I'm going to close it.

https://github.com/llvm/llvm-project/pull/68096