[LLDB][PPC64] Fixed next blocked forever at same line

Summary:
The PC corresponding to the breakpoint was being calculated wrongly,
which was causing LLDB to never go past the first breakpoint, when
there was a second one adjacent to it.

Reviewers: clayborg, labath

Reviewed By: clayborg, labath

Subscribers: anajuliapc, alexandreyy, lbianc

Differential Revision: https://reviews.llvm.org/D43344
Patch by Leandro Lupori <leandro.lupori@gmail.com>.

llvm-svn: 325728