x86: make start_secondary() static

start_secondary() needlessly became global.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/smpboot.c

@@ -299,7 +299,7 @@ static void __cpuinit smp_callin(void)
 /*
  * Activate a secondary processor.
  */
-void __cpuinit start_secondary(void *unused)
+static void __cpuinit start_secondary(void *unused)
 {
 	/*
 	 * Don't put *anything* before cpu_init(), SMP booting is too