[MIPS] IP27: Fix modpost warning.

  MODPOST vmlinux.o
WARNING: vmlinux.o(.text+0x3180): Section mismatch: reference to .init.text:per_cpu_init (between 'prom_init_secondary' and 'alloc_cpupda')
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/sgi-ip27/ip27-smp.c

@@ -181,7 +181,7 @@ void __init prom_boot_secondary(int cpu, struct task_struct *idle)
 		0, (void *) sp, (void *) gp);
 }
 
-void prom_init_secondary(void)
+void __cpuinit prom_init_secondary(void)
 {
 	per_cpu_init();
 	local_irq_enable();