[PowerPC] Correctly specify the cache line size for Power 7, 8 and 9.

Fixes PPCTTIImpl::getCacheLineSize() returning the wrong cache line size for
newer ppc processors.

Commiting on behalf of Stefan Pintilie.
Differential Revision: https://reviews.llvm.org/D33656

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304317 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed