On PowerPC, the cache-flush instructions dcbf and icbi are treated as
loads. On FreeBSD, add PROT_READ page protection flag before flushing
cache.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175646 91177308-0d34-0410-b5e6-96231b3b80d8
Formatting, grammar

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175647 91177308-0d34-0410-b5e6-96231b3b80d8