[llvm-mca] Remove a stale TODO comment. NFC

Starting from revision r344334, we can now describe optimizable
register-register moves in the machine scheduling models.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344797 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed