CPU: Avoid using unititialized error variable in disable_nonboot_cpus()

If there's only one CPU online when disable_nonboot_cpus() is called,
the error variable will not be initialized and that may lead to
erroneous behavior.  Fix this issue by initializing error in
disable_nonboot_cpus() as appropriate.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 3097382..8b92539 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -394,7 +394,7 @@
 
 int disable_nonboot_cpus(void)
 {
-	int cpu, first_cpu, error;
+	int cpu, first_cpu, error = 0;
 
 	cpu_maps_update_begin();
 	first_cpu = cpumask_first(cpu_online_mask);