ppc: Fix record of HTM instructions

ppc: Fix record of HTM instructions

The patch fixes the record support of Hardware Transactional Memory
instructions on Power. It also solves a large number of unexpected failures
from gdb.reverse testcases sigall-precsave.exp and sigall-reverse.exp that
occur on distros which glibc uses HTM instructions.

gdb/ChangeLog
2016-08-18  Edjunior Barbosa Machado  <emachado@linux.vnet.ibm.com>

	* rs6000-tdep.c (ppc_process_record_op31): Handle HTM instructions.