[llvm-mca] Remove flag -max-retire-per-cycle, and update the docs.

This is done in preparation for D45259.
With D45259, models can specify the size of the reorder buffer, and the retire
throughput directly via tablegen.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@329274 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed