[PATCH] powerpc/kprobes: Fix build error with kprobes disabled.

[Aneesh Kumar K.V]

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.ku...@linux.ibm.com>
---
 arch/powerpc/kernel/stacktrace.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
index 26a50603177c..8dd6ba0c7d35 100644
--- a/arch/powerpc/kernel/stacktrace.c
+++ b/arch/powerpc/kernel/stacktrace.c
@@ -168,13 +168,14 @@ save_stack_trace_tsk_reliable(struct task_struct *tsk,
                 * arch-dependent code, they are generic.
                 */
                ip = ftrace_graph_ret_addr(tsk, &graph_idx, ip, NULL);
-
+#ifdef CONFIG_KPROBES
                /*
                 * Mark stacktraces with kretprobed functions on them
                 * as unreliable.
                 */
                if (ip == (unsigned long)kretprobe_trampoline)
                        return 1;
+#endif
 
                if (!trace->skip)
                        trace->entries[trace->nr_entries++] = ip;
-- 
2.17.0