Add specific ppc64le hardware watchpoint handler

Summary: Add hardware watchpoint funcionality for ppc64le

Reviewers: clayborg, zturner

Reviewed By: clayborg

Subscribers: eugene, clayborg, zturner, lbianc, gut, nemanjai, alexandreyy, kbarton, lldb-commits

Differential Revision: https://reviews.llvm.org/D38897
Patch by Ana Julia Caetano <ana.caetano@eldorado.org.br>

llvm-svn: 316772