oprofile/x86: return -EBUSY if counters are already reserved

In case a counter is already reserved by the watchdog or perf_event
subsystem, oprofile ignored this counters silently. This case is
handled now and oprofile_setup() now reports an error.

Signed-off-by: Robert Richter <robert.richter@amd.com>
diff --git a/arch/x86/oprofile/nmi_int.c b/arch/x86/oprofile/nmi_int.c
index c0c21f2..9f001d9 100644
--- a/arch/x86/oprofile/nmi_int.c
+++ b/arch/x86/oprofile/nmi_int.c
@@ -357,7 +357,10 @@
 	 */
 
 	/* Assume saved/restored counters are the same on all CPUs */
-	model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
+	err = model->fill_in_addresses(&per_cpu(cpu_msrs, 0));
+	if (err)
+		goto fail;
+
 	for_each_possible_cpu(cpu) {
 		if (!cpu)
 			continue;