x86: don't pretend that non-framepointer stack traces are reliable

Without frame pointers enabled, the x86 stack traces should not
pretend to be reliable; instead they should just be what they are:
unreliable.

The effect of this is that they have a '?' printed in the stacktrace,
to warn the reader that these entries are guesses rather than known
based on more reliable information.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/dumpstack.c

@@ -99,7 +99,7 @@ print_context_stack(struct thread_info *tinfo,
 				frame = frame->next_frame;
 				bp = (unsigned long) frame;
 			} else {
-				ops->address(data, addr, bp == 0);
+				ops->address(data, addr, 0);
 			}
 			print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 		}