Power PC, add the two privileged Transactional Memory instructions.

The initial Transactional Memory instruction patch did not include the two
privileged (OS) instructions.  This patch adds support for the two
instructions, treclaim and trechkpt.

The patch if for Bugzilla 325751.

git-svn-id: svn://svn.valgrind.org/vex/trunk@2784 8f6e269a-dfd6-0310-a8e1-e2731360e62c