[llvm-mca] Add file header to RetireControlUnit.cpp.

Strictly speaking, this is not necessary for .cpp files. However, other .cpp
files from this same tool have it. This also matches what we do in other tools.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332334 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed