Add recording support for the ISA 3.1 PowerPC instructions.

This patch adds support for the PowerPC ISA 3.1 instructions to the PowerPC
gdb instruction recording routines.  Case statement entries are added to a
number of the existing routines for recording the 32-bit word instructions.
A few new functions were added to handle the new word instructions.  The 64-bit
prefix instructions are all handled by a set of new routines.  The function
ppc_process_prefix_instruction() is the primary function to handle the
prefixed instructions. It calls additional functions to handle specific
sets of prefixed instructions.  These new functions are:
  ppc_process_record_prefix_vsx_d_form(),
  ppc_process_record_prefix_store_vsx_ds_form(),
  ppc_process_record_prefix_op34(),
  ppc_process_record_prefix_op33(),
  ppc_process_record_prefix_op32(),
  ppc_process_record_prefix_store(),
  ppc_process_record_prefix_op59_XX3(),
  ppc_process_record_prefix_op42().