perf probe: Use pr_debug for debug message

Use pr_debug() for "missing vmlinux" debugging message.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091207170059.19230.51459.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-probe.c

@@ -194,7 +194,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 		if (session.need_dwarf)
 			die("Could not open vmlinux/module file.");
 
-		pr_warning("Could not open vmlinux/module file."
+		pr_debug("Could not open vmlinux/module file."
 			 " Try to use symbols.\n");
 		goto end_dwarf;
 	}