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

In more recent Linux kernels (including those with 47 bit VMAs) the layout of
virtual memory for powerpc64 changed causing the memory sanitizer to not
work properly.  This patch adjusts the memory ranges in the tables for the
memory sanitizer to work on the newer kernels while continuing to work on the
older ones as well.

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

llvm-svn: 317802