x86 apic_32.c section fix

CONFIG_HOTPLUG_CPU=y:

WARNING: vmlinux.o(.text+0x2390d): Section mismatch: reference to .init.text.5:setup_local_APIC (between 'start_secondary' and 'check_tsc_warp')

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>