powerpc/kprobes: Fix build error with kprobes disabled.

[Michael Ellerman]

On Tue, 2018-05-22 at 09:08:20 UTC, "Aneesh Kumar K.V" wrote:
> arch/powerpc/kernel/stacktrace.c: In function ‘save_stack_trace_tsk_reliable’:
> arch/powerpc/kernel/stacktrace.c:176:28: error: ‘kretprobe_trampoline’ undeclared (first use in this function); did you mean ‘is_ftrace_trampoline’?
>    if (ip == (unsigned long)kretprobe_trampoline)
>                             ^~~~~~~~~~~~~~~~~~~~
>                             is_ftrace_trampoline
> arch/powerpc/kernel/stacktrace.c:176:28: note: each undeclared identifier is reported only once for each function it appears in
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/5e3f0d15ae5f95bdde8d092a0884d2

cheers