Revert "[POWERPC] Add compat handler for PTRACE_GETSIGINFO"

This reverts commit e4cc58944c, as
requested by Roland McGrath, because compat_ptrace_request (added in
commit e16b278164, "ptrace:
compat_ptrace_request siginfo") now handles this case.

Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/ppc32.h

@@ -135,6 +135,4 @@ struct ucontext32 {
 	struct mcontext32	uc_mcontext;
 };
 
-extern int copy_siginfo_to_user32(struct compat_siginfo __user *d, siginfo_t *s);
-
 #endif  /* _PPC64_PPC32_H */