- Add PTRACE_GET_DEBUGREG/PTRACE_SET_DEBUGREG. The definition is
  as follows:

/*
 * Get or set a debug register. The first 16 are DABR registers and the
 * second 16 are IABR registers.
 */
#define PTRACE_GET_DEBUGREG    25
#define PTRACE_SET_DEBUGREG    26

  DABR == data breakpoint and IABR = instruction breakpoint in IBM
  speak. We could split out the IABR into 2 more ptrace calls but I
  figured there was no need and 16 DABR registers should be more
  than enough (POWER4/POWER5 have one).

- Add 2 new SIGTRAP si_codes: TRAP_HWBKPT and TRAP_BRANCH. I couldnt
  find any standards on either of these so I copied what ia64 is
  doing. Again this might be better placed in
  include/asm-generic/siginfo.h
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>