Move the CC analysis implementation to its own .cpp file instead of
duplicating it and artificually using functions in PPCISelLowering.cpp
and PPCFastISel.cpp. Follow-up to the same change done for X86, ARM, and
AArch64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@352444 91177308-0d34-0410-b5e6-96231b3b80d8
