parisc: Wire up PTRACE_GETREGS/PTRACE_SETREGS for compat case

Wire up the missing ptrace requests PTRACE_GETREGS, PTRACE_SETREGS,
PTRACE_GETFPREGS and PTRACE_SETFPREGS when running 32-bit applications
on 64-bit kernels.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org # 4.7+