[PowerPC][tsan] Update tsan to handle changed memory layouts in newer kernels

In more recent Linux kernels with 47 bit VMAs the layout of virtual memory
for powerpc64 changed causing the thread sanitizer to not work properly. This
patch adds support for 47 bit VMA kernels for powerpc64.

Tested on several 4.x and 3.x kernel releases.

llvm-svn: 318044