sh: stacktrace: Add reliability checks in address saving ops.

This adopts the reliability checks from the x86 stacktrace code so known
bad addresses are not recorded in the stack trace buffer.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/stacktrace.c b/arch/sh/kernel/stacktrace.c
index 45b1add..a0f497b 100644
--- a/arch/sh/kernel/stacktrace.c
+++ b/arch/sh/kernel/stacktrace.c
@@ -38,6 +38,9 @@
 {
 	struct stack_trace *trace = data;
 
+	if (!reliable)
+		return;
+
 	if (trace->skip > 0) {
 		trace->skip--;
 		return;
@@ -67,6 +70,9 @@
 {
 	struct stack_trace *trace = (struct stack_trace *)data;
 
+	if (!reliable)
+		return;
+
 	if (in_sched_functions(addr))
 		return;